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Summary of Significant Accounting Policies

Description of Business

EnerSys (the “Company”) and its predecessor companies have been manufacturers of industrial batteries for over 125 years. EnerSys is a global leader in stored energy solutions for industrial applications. The Company manufactures, markets and distributes industrial batteries and related products such as chargers, outdoor cabinet enclosures, power equipment and battery accessories, and provides related after-market and customer-support services for its products. With the recent Alpha acquisition, the Company is also a provider of highly integrated power solutions and services to broadband, telecom, renewable and industrial customers.

Principles of Consolidation

The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries and any partially owned subsidiaries that the Company has the ability to control. Control generally equates to ownership percentage, whereby investments that are more than 50% owned are generally consolidated, investments in affiliates of 50% or less but greater than 20% are generally accounted for using the equity method, and investments in affiliates of 20% or less are accounted for using the cost method. All intercompany transactions and balances have been eliminated in consolidation.

Foreign Currency Translation

Results of foreign operations of subsidiaries, whose functional currency is the local currency, are translated into U.S. dollars using average exchange rates during the periods. The assets and liabilities are translated into U.S. dollars using exchange rates as of the balance sheet dates. Gains or losses resulting from translating the foreign currency financial statements are accumulated as a separate component of accumulated other comprehensive income (“AOCI”) in EnerSys’ stockholders’ equity and noncontrolling interests.

Transaction gains and losses resulting from exchange rate changes on transactions denominated in currencies other than the functional currency of the applicable subsidiary are included in the Consolidated Statements of Income, within “Other (income) expense, net”, in the year in which the change occurs.

Revenue Recognition

Revenue for the years ended March 31, 2018 and 2017 were recognized under ASC 605, Revenue Recognition, when (i) persuasive evidence of an arrangement existed, (ii) delivery occurred or services were rendered, (iii) the price was fixed or determinable and (iv) collectibility was reasonably assured.

ASC 606, Revenue from Contracts with Customers, was adopted for the fiscal year beginning April 1, 2018.

Concurrent with the adoption of the new standard, the Company has updated its revenue recognition policy as follows:

The Company determines revenue recognition by applying the following steps:

1. identify the contract with a customer;

2. identify the performance obligations in the contract;

3. determine the transaction price;

4. allocate the transaction price to the performance obligations; and

5. recognize revenue as the performance obligations are satisfied.

The Company recognizes revenue when (or as) performance obligations are satisfied by transferring control of the performance obligation to a customer. Control of a performance obligation may transfer to the customer either at a point in time or over time depending on an evaluation of the specific facts and circumstances for each contract, including the terms and conditions of the contract as agreed with the customer, as well as the nature of the products or services to be provided.

The Company's primary performance obligation to its customers is the delivery of finished goods and products, pursuant to

purchase orders. Control of the products sold typically transfers to its customers at the point in time when the goods are shipped

as this is also when title generally passes to its customers under the terms and conditions of our customer arrangements.

Each customer purchase order sets forth the transaction price for the products and services purchased under that arrangement. Some customer arrangements include variable consideration, such as volume rebates, some of which depend upon the customers meeting specified performance criteria, such as a purchasing level over a period of time. The Company uses judgment to estimate the most likely amount of variable consideration at each reporting date. When estimating variable consideration the Company also applies judgment when considering the probability of whether a reversal of revenue could occur and only recognize revenue subject to this constraint.

Service revenues related to the work performed for the Company’s customers by its maintenance technicians generally represent a separate and distinct performance obligation. Control for these services passes to the customer as the services are performed. Service revenues for the twelve months of fiscal 2019 amounted to $157,236.

A small portion of the Company's customer arrangements oblige the Company to create customized products for its customers that require the bundling of both products and services into a single performance obligation because the individual products and services that are required to fulfill the customer requirements do not meet the definitions for a distinct performance obligation. These customized products generally have no alternative use to the Company and the terms and conditions of these arrangements give the Company the enforceable right to payment for performance completed to date, including a reasonable profit margin. For these arrangements, control transfers over time and the Company measures progress towards completion by selecting the input or output method that best depicts the transfer of control of the underlying goods and services to the customer for each respective arrangement. Methods used by the Company to measure progress toward completion include labor hours, costs incurred and units of production. Revenues recognized over time for the twelve months of fiscal 2019 amounted to $100,809.

On March 31, 2019, the aggregate transaction price allocated to unsatisfied (or partially unsatisfied) performance obligations was approximately $66,088, of which, the Company estimates that approximately $60,443 will be recognized as revenue in fiscal 2020 and $5,645 in fiscal 2021.

The Company's typical payment terms are 30 days and sales arrangements do not contain any significant financing component for its customers.

Any payments that are received from a customer in advance, prior to the satisfaction of a related performance obligation and billings in excess of revenue recognized, are deferred and treated as a contract liability. Advance payments and billings in excess of revenue recognized are classified as current or non-current based on the timing of when recognition of revenue is expected. As of March 31, 2019, the current and non-current portion of contract liabilities were $15,162 and $6,360, respectively. Revenues recognized during the twelve months of fiscal 2019, that were included in the contract liability at the beginning of the fiscal year, amounted to $6,132.

Amounts representing work completed and not billed to customers represent contract assets and are reported as a component of Prepaid and Other Current Assets in the Consolidated Balance Sheets. Contract assets as of March 31, 2019 were $38,778. In conjunction with the April 1, 2018 adoption of ASC 606, $24,810 was reclassified to contract assets, which was previously recorded in inventories and accounts receivables. Also as of April 1, 2018, $9,387 and $7,094, were identified as contract liabilities, current and non-current, that were recorded in Accrued Expenses and Other Liabilities, respectively.

The Company uses historic customer product return data as a basis of estimation for customer returns and records the reduction of sales at the time revenue is recognized. At March 31, 2019, the right of return asset related to the value of inventory anticipated to be returned from customers was $2,667 and refund liability representing amounts estimated to be refunded to customers was $5,153. These are shown under Prepaid and Other Current Assets and Accrued Expenses, respectively.

Freight charges billed to customers are included in sales and the related shipping costs are included in cost of sales in the Consolidated Statements of Income. If shipping activities are performed after a customer obtains control of a product, the Company applies a policy election to account for shipping as an activity to fulfill the promise to transfer the product to the customer.

The Company applies a policy election to exclude transaction taxes collected from customers from sales when the tax is both imposed on and concurrent with a specific revenue-producing transaction.

The Company generally provides customers with a product warranty that provides assurance that the products meet standard specifications and are free of defects. The Company maintains a reserve for claims incurred under standard product warranty programs. Performance obligations related to service warranties are not material to the Consolidated Financial Statements.

The Company pays sales commissions to its sales representatives, which may be considered as incremental costs to obtain a contract. However, since the recoverability period is less than one year, the Company has utilized the practical expedient to record these costs of obtaining a contract as an expense as they are incurred.

Warranties

The Company’s products are warranted for a period ranging from one to twenty years for reserve power batteries and for a period ranging from one to seven years for motive power batteries. The Company provides for estimated product warranty expenses when the related products are sold. The assessment of the adequacy of the reserve includes a review of open claims and historical experience.

Cash and Cash Equivalents

Cash and cash equivalents include all highly liquid investments with an original maturity of three months or less when purchased.

Concentration of Credit Risk

Financial instruments that subject the Company to potential concentration of credit risk consist principally of short-term cash investments and trade accounts receivable. The Company invests its cash with various financial institutions and in various investment instruments limiting the amount of credit exposure to any one financial institution or entity. The Company has bank deposits that exceed federally insured limits. In addition, certain cash investments may be made in U.S. and foreign government bonds, or other highly rated investments guaranteed by the U.S. or foreign governments. Concentration of credit risk with respect to trade receivables is limited by a large, diversified customer base and its geographic dispersion. The Company performs ongoing credit evaluations of its customers’ financial condition and requires collateral, such as letters of credit, in certain circumstances.

Accounts Receivable

The Company maintains allowances for doubtful accounts for estimated losses resulting from the inability of customers to make required payments. The allowance is based on management’s estimate of uncollectible accounts, analysis of historical data and trends, as well as reviews of all relevant factors concerning the financial capability of its customers. Accounts receivable are considered to be past due based on when payments are received compared to the customer’s credit terms. Accounts are written off when management determines the account is uncollectible.

Inventories

Inventories are stated at the lower of cost or market. Cost is determined using the first-in, first-out (FIFO) method. The cost of inventory consists of material, labor, and associated overhead.

Property, Plant, and Equipment

Property, plant, and equipment are recorded at cost and include expenditures that substantially increase the useful lives of the assets. Depreciation is provided using the straight-line method over the estimated useful lives of the assets as follows: 10 to 33 years for buildings and improvements and 3 to 15 years for machinery and equipment.

Maintenance and repairs are expensed as incurred. Interest on capital projects is capitalized during the construction period.

Business Combinations

The Company records an acquisition using the acquisition method of accounting and recognizes the assets acquired and liabilities assumed at their fair values as of the date of the acquisition. The excess of the purchase price over the net tangible and

intangible assets is recorded to goodwill. The results of operations of the acquired business are included in the Company’s operating results from the date of acquisition.

Goodwill and Other Intangible Assets

Goodwill and indefinite-lived trademarks are tested for impairment at least annually and whenever events or circumstances occur indicating that a possible impairment may have been incurred. Goodwill is tested for impairment by determining the fair value of the Company’s reporting units. These estimated fair values are based on financial projections, certain cash flow measures, and market capitalization.

The Company estimates the fair value of its reporting units using a weighting of fair values derived from both the income approach and the market approach. Under the income approach, the Company calculates the fair value of a reporting unit based on the present value of estimated future cash flows. Cash flow projections are based on management's estimates of revenue growth rates and operating margins, taking into consideration industry and market conditions. The discount rate used is based on the weighted-average cost of capital adjusted for the relevant risk associated with business-specific characteristics and the uncertainty related to the business's ability to execute on the projected cash flows. The market approach estimates fair value based on market multiples of revenue and earnings derived from comparable publicly-traded companies with similar operating and investment characteristics as the reporting unit. The weighting of the fair value derived from the market approach ranges from 0% to 50% depending on the level of comparability of these publicly-traded companies to the reporting unit.

In order to assess the reasonableness of the calculated fair values of its reporting units, the Company also compares the sum of the reporting units' fair values to its market capitalization and calculates an implied control premium (the excess of the sum of the reporting units' fair values over the market capitalization). The Company evaluates the control premium by comparing it to control premiums of recent comparable market transactions.

The Company assesses whether indefinite-lived intangible assets impairment exists using both the qualitative and quantitative assessments. The qualitative assessment involves determining whether events or circumstances exist that indicate it is more likely than not that the fair value of an indefinite-lived intangible asset is less than its carrying amount. If based on this qualitative assessment, the Company determines it is more likely than not that the fair value of an indefinite-lived intangible asset is less than its carrying amount or if the Company elects not to perform a qualitative assessment, a quantitative assessment is performed to determine whether an indefinite-lived intangible asset impairment exists. The Company tests the indefinite-lived intangible assets for impairment by comparing the carrying value to the fair value based on current revenue projections of the related operations, under the relief from royalty method. Any excess of the carrying value over the amount of fair value is recognized as an impairment. Any such impairment is recognized in the reporting period in which it has been identified.

Finite-lived assets such as customer relationships, technology, trademarks, licenses, and non-compete agreements are amortized on a straight-line basis over their estimated useful lives, generally over periods ranging from 3 to 20 years. The Company reviews the carrying values of these assets for possible impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable based on undiscounted estimated cash flows expected to result from its use and eventual disposition. The Company continually evaluates the reasonableness of the useful lives of these assets.

Impairment of Long-Lived Assets

The Company reviews the carrying values of its long-lived assets to be held and used for possible impairment whenever events or changes in circumstances indicate that the carrying value may not be recoverable, based on undiscounted estimated cash flows expected to result from its use and eventual disposition. The factors considered by the Company in performing this assessment include current operating results, trends and other economic factors. In assessing the recoverability of the carrying value of a long-lived asset, the Company must make assumptions regarding future cash flows and other factors. If these estimates or the related assumptions change in the future, the Company may be required to record an impairment loss for these assets.

Environmental Expenditures

The Company records a loss and establishes a reserve for environmental remediation liabilities when it is probable that an asset has been impaired or a liability exists and the amount of the liability can be reasonably estimated. Reasonable estimates involve judgments made by management after considering a broad range of information including notifications, demands or settlements that have been received from a regulatory authority or private party, estimates performed by independent engineering companies and outside counsel, available facts, existing and proposed technology, the identification of other potentially

responsible parties, their ability to contribute and prior experience. These judgments are reviewed quarterly as more information is received and the amounts reserved are updated as necessary. However, the reserves may materially differ from ultimate actual liabilities if the loss contingency is difficult to estimate or if management’s judgments turn out to be inaccurate. If management believes no best estimate exists, the minimum probable loss is accrued.

Derivative Financial Instruments

The Company utilizes derivative instruments to mitigate volatility related to interest rates, lead prices and foreign currency exposures. The Company does not hold or issue derivative financial instruments for trading or speculative purposes. The Company recognizes derivatives as either assets or liabilities in the accompanying Consolidated Balance Sheets and measures those instruments at fair value. Changes in the fair value of those instruments are reported in AOCI if they qualify for hedge accounting or in earnings if they do not qualify for hedge accounting. Derivatives qualify for hedge accounting if they are designated as hedge instruments and if the hedge is highly effective in achieving offsetting changes in the fair value or cash flows of the asset or liability hedged. Effectiveness is measured on a regular basis using statistical analysis and by comparing the overall changes in the expected cash flows on the lead and foreign currency forward contracts with the changes in the expected all-in cash outflow required for the lead and foreign currency purchases. This analysis is performed on the initial purchases quarterly that cover the quantities hedged. Accordingly, gains and losses from changes in derivative fair value of effective hedges are deferred and reported in AOCI until the underlying transaction affects earnings.

The Company has commodity, foreign exchange and interest rate hedging authorization from the Board of Directors and has established a hedging and risk management program that includes the management of market and counterparty risk. Key risk control activities designed to ensure compliance with the risk management program include, but are not limited to, credit review and approval, validation of transactions and market prices, verification of risk and transaction limits, portfolio stress tests, sensitivity analyses and frequent portfolio reporting, including open positions, determinations of fair value and other risk management metrics.

Market risk is the potential loss the Company and its subsidiaries may incur as a result of price changes associated with a particular financial or commodity instrument. The Company utilizes forward contracts, options, and swaps as part of its risk management strategies, to minimize unanticipated fluctuations in earnings caused by changes in commodity prices, interest rates and / or foreign currency exchange rates. All derivatives are recognized on the balance sheet at their fair value, unless they qualify for the Normal Purchase Normal Sale exemption.

Credit risk is the potential loss the Company may incur due to the counterparty’s non-performance. The Company is exposed to credit risk from interest rate, foreign currency and commodity derivatives with financial institutions. The Company has credit policies to manage their credit risk, including the use of an established credit approval process, monitoring of the counterparty positions and the use of master netting agreements.

The Company has elected to offset net derivative positions under master netting arrangements. The Company does not have any positions involving cash collateral (payables or receivables) under a master netting arrangement as of March 31, 2019 and 2018.

The Company does not have any credit-related contingent features associated with its derivative instruments.

Fair Value of Financial Instruments

The Company groups its recurring, non-recurring and disclosure-only fair value measurements into the following levels when making fair value measurement disclosures:



Level 1		Inputs are unadjusted quoted prices in active markets for identical assets or liabilities.

Level 2		Inputs are quoted prices for similar assets or liabilities in an active market, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable and market-corroborated inputs which are derived principally from or corroborated by observable market data.

Level 3		Inputs are derived from valuation techniques in which one or more significant inputs or value drivers are unobservable.

Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (an exit price). The Company and its subsidiaries use, as appropriate, a market approach (generally, data from market transactions), an income approach (generally, present value techniques and option-pricing models), and / or a cost approach (generally, replacement cost) to measure the fair value of an asset or liability. These valuation approaches incorporate inputs such as observable, independent market data and / or unobservable data that management believes are predicated on the assumptions market participants would use to price an asset or liability. These inputs may incorporate, as applicable, certain risks such as nonperformance risk, which includes credit risk.

Lead contracts, foreign currency contracts and interest rate contracts generally use an income approach to measure the fair value of these contracts, utilizing readily observable inputs, such as forward interest rates (e.g., London Interbank Offered Rate—“LIBOR”), forward foreign currency exchange rates (e.g., GBP and euro) and commodity prices (e.g., London Metals Exchange), as well as inputs that may not be observable, such as credit valuation adjustments. When observable inputs are used to measure all or most of the value of a contract, the contract is classified as Level 2. Over-the-counter (OTC) contracts are valued using quotes obtained from an exchange, binding and non-binding broker quotes. Furthermore, the Company obtains independent quotes from the market to validate the forward price curves. OTC contracts include forwards, swaps and options. To the extent possible, fair value measurements utilize various inputs that include quoted prices for similar contracts or market-corroborated inputs.

When unobservable inputs are significant to the fair value measurement, the asset or liability is classified as Level 3. Additionally, Level 2 fair value measurements include adjustments for credit risk based on the Company’s own creditworthiness (for net liabilities) and its counterparties’ creditworthiness (for net assets). The Company assumes that observable market prices include sufficient adjustments for liquidity and modeling risks. The Company did not have any fair value measurements that transferred between Level 2 and Level 3 as well as Level 1 and Level 2.

Income Taxes

The Company accounts for income taxes using the asset and liability approach, which requires deferred tax assets and liabilities be recognized using enacted tax rates to measure the effect of temporary differences between book and tax bases on recorded assets and liabilities. Valuation allowances are recorded to reduce deferred tax assets, if it is more likely than not some portion or all of the deferred tax assets will not be realized. The need to establish valuation allowances against deferred tax assets is assessed quarterly. The primary factors used to assess the likelihood of realization are expected reversals of taxable temporary timing differences, forecasts of future taxable income and available tax planning strategies that could be implemented to realize the net deferred tax assets.

The Company recognizes tax related interest and penalties in income tax expense in its Consolidated Statement of Income.

With respect to accounting for uncertainty in income taxes, the Company evaluates tax positions to determine whether the benefits of tax positions are more likely than not of being sustained upon audit based on the technical merits of the tax position. For tax positions that are more likely than not of being sustained upon audit, the Company recognizes the largest amount of the benefit that is greater than 50% likely of being realized upon ultimate settlement. For tax positions that are not more likely than not of being sustained upon audit, the Company does not recognize any portion of the benefit. If the more likely than not threshold is not met in the period for which a tax position is taken, the Company may subsequently recognize the benefit of that tax position if the tax matter is effectively settled, the statute of limitations expires, or if the more likely than not threshold is met in a subsequent period.

No additional income taxes have been provided for any undistributed foreign earnings or any additional outside basis difference inherent in these entities, as these amounts continue to be indefinitely reinvested in foreign operations.

Deferred Financing Fees

Debt issuance costs that are incurred by the Company in connection with the issuance of debt are deferred and amortized to interest expense over the life of the underlying indebtedness, adjusted to reflect any early repayments and are shown as a deduction from long-term debt.

Stock-Based Compensation Plans

The Company measures the cost of employee services received in exchange for the award of an equity instrument based on the grant-date fair value of the award, with such cost recognized over the applicable vesting period.

Market and Performance condition-based awards

The Company grants market condition-based awards and performance condition-based awards.

Prior to fiscal 2016, the Company granted market condition-based awards (“MSU”). These units cliff vested on the third anniversary of the date of grant. These share units were converted into between zero and two shares of common stock for each unit granted at the end of a three-year performance cycle. The conversion ratio was calculated by dividing the average closing share price of the Company’s common stock during the ninety calendar days immediately preceding the vesting date by the average closing share price of the Company’s common stock during the ninety calendar days immediately preceding the grant date, with the resulting quotient capped at two. This quotient was then multiplied by the number of share units granted to yield the number of shares of common stock to be delivered on the vesting date. The fair value of the share units was estimated at the date of grant using a binomial lattice model with the following assumptions: a risk-free interest rate, dividend yield, time to maturity and expected volatility.

Beginning with fiscal 2017, the Company granted market condition-based awards (“TSR”). A participant may earn between 0% to 200% of the number of awards granted, based on the total shareholder return of the Company's common stock over a three-year period. The awards cliff vest on the third anniversary of the date of grant and are settled in common stock on the first anniversary of the vesting date. The TSR is calculated by dividing the sixty or ninety calendar day average price at end of the period (as applicable) and the reinvested dividends thereon by such sixty or ninety calendar day average price at start of the period. The maximum number of awards earned is capped at 200% of the target award. Additionally, no payout will be awarded in the event that the TSR at the vesting date reflects less than a 25% return from the average price at the grant date. These share units are similar to the share units granted prior to fiscal 2016, except that under these awards, the targets are more difficult to achieve as they are tied to the TSR of a defined peer group. The fair value of these awards is estimated at the date of grant, using a Monte Carlo Simulation.

The Company recognizes compensation expense using the straight-line method over the life of the market condition-based awards except for those issued to certain retirement-eligible participants, which are expensed on an accelerated basis.

In fiscal 2019, the Company granted performance condition-based awards (“PSU”). A participant may earn between 0% to 200% of the number of awards granted, based on the Company’s cumulative adjusted earnings per share performance over a three-year period. The vesting of these awards are contingent upon meeting or exceeding performance conditions. The awards cliff vest on the third anniversary of the date of grant and are settled in common stock on the first anniversary of the vesting date. The maximum number of awards earned is capped at 200% of the target award. Expense for the performance condition based award is recorded when the achievement of the performance condition is considered probable of achievement and is recorded on a straight-line basis over the requisite service period. If such performance criteria are not met, no compensation cost is recognized and any recognized compensation cost is reversed. The closing stock price on the date of grant, adjusted for a discount to reflect the illiquidity inherent in the PSUs, represents the grant-date fair value for these awards.

Restricted Stock Units

The fair value of restricted stock units is based on the closing market price of the Company’s common stock on the date of grant. These awards generally vest, and are settled in common stock, at 25% per year, over a four year period from the date of grant. The Company recognizes compensation expense using the straight-line method over the life of the restricted stock units.

Stock Options

The fair value of the options granted is estimated at the date of grant using the Black-Scholes option-pricing model utilizing assumptions based on historical data and current market data. The assumptions include expected term of the options, risk-free interest rate, expected volatility, and dividend yield. The expected term represents the expected amount of time that options granted are expected to be outstanding, based on historical and forecasted exercise behavior. The risk-free rate is based on the rate at the grant date of zero-coupon U.S. Treasury Notes with a term equal to the expected term of the option. Expected volatility is estimated using historical volatility rates based on historical weekly price changes over a term equal to the expected term of the options. The Company’s dividend yield is based on historical data. The Company recognizes compensation expense using the straight-line method over the vesting period of the options except for those issued to certain retirement-eligible participants, which are expensed on an accelerated basis.

Forfeitures

Forfeitures of share-based awards are estimated at the time of grant and revised, if necessary, in subsequent periods if actual

forfeitures differ from those estimates.

Earnings Per Share

Basic earnings per common share (“EPS”) are computed by dividing net earnings attributable to EnerSys stockholders by the weighted-average number of common shares outstanding for the period. Diluted EPS reflects the potential dilution that would occur if securities or other contracts to issue common stock were exercised or converted into common stock. At March 31, 2019, 2018 and 2017, the Company had outstanding stock options, restricted stock units, market and performance condition-based awards, which could potentially dilute basic earnings per share in the future.

Segment Reporting

A segment for reporting purposes is based on the financial performance measures that are regularly reviewed by the chief operating decision maker to assess segment performance and to make decisions about a public entity’s allocation of resources. Based on this guidance, the Company reports its segment results based upon the three geographical regions of operations.


•	Americas, which includes North and South America, with segment headquarters in Reading, Pennsylvania, U.S.A.,


•	EMEA, which includes Europe, the Middle East and Africa, with segment headquarters in Zug, Switzerland, and


•	Asia, which includes Asia, Australia and Oceania, with segment headquarters in Singapore.

Recently Adopted Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” providing guidance on revenue from contracts with customers that supersedes most current revenue recognition guidance, including industry-specific guidance. The underlying principle is that an entity will recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services.

The Company adopted this standard on April 1, 2018 using the modified retrospective transition method. Under the modified retrospective transition method, the cumulative effect of applying Topic 606 to all contracts where all revenue has not been completely recognized under previously existing accounting principles that are not completed as of the date of adoption is recorded as an adjustment to the opening balance of retained earnings (if applicable) while the comparative periods are not restated and continue to be reported under the accounting standards in effect for those periods. There was no cumulative effect of adopting the standard at the date of initial application in retained earnings.

In March 2017, the FASB issued ASU No. 2017-07, “Compensation—Retirement Benefits (Topic 715)”, which requires an entity to report the service cost component of pension and other postretirement benefit costs in the same line item as other compensation costs. The other components of net (benefit) cost will be required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations. This standard is effective for interim and annual reporting periods beginning after December 15, 2017, with early adoption permitted and requires the retrospective method to be applied to all periods presented. The Company adopted this guidance effective April 1, 2018. The service cost component of pension expense continues to be recognized in cost of goods sold whereas other components of pension expense have been reclassified to “Other (income) expense, net” in the Consolidated Statements of Income. The Company reclassified $1,464 and $1,252 from “Cost of goods sold” relating to fiscal 2018 and 2017, respectively, to “Other (income) expense, net” in the Consolidated Statements of Income.

Accounting Pronouncements Issued But Not Adopted as of March 31, 2019

In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842)”, which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e. lessees and lessors). This update requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase of the leased asset by the lessee. This classification will determine whether the lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their

classification. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. This update is effective for annual periods beginning after December 15, 2018, using a modified retrospective approach, with early adoption permitted.

ASC 842 will be effective for the Company on April 1, 2019. There are a number of optional practical expedients made available to simplify the transition of the new standard. The Company has made the following elections:


•	to adopt the optional transition method defined within ASU 2018-11 and not restate comparative prior periods but instead recognize a cumulative effect adjustment to the opening balance of retained earnings in the period of adoption;


•	to elect the package of three practical expedients addressing whether a contract contains a lease, lease classification and initial direct costs;

to combine lease and non-lease components as a single component for all asset classes;


•	to use a portfolio approach to determine the incremental borrowing rate; and


•	to apply the short-term lease exception to leases that, at the commencement date, has a lease term of 12 months or less and does not include an option to purchase the underlying asset that the lessee is reasonably certain to exercise.

During fiscal 2019, the Company made progress on implementing the new standard which included surveying the Company’s businesses, assessing the Company’s portfolio of leases and compiling a central repository of active leases. The Company evaluated key policy elections and considerations under the standard which the Company will utilize to develop an internal policy to address the new standard requirements. Additionally, the Company selected a lease accounting software solution to support the new reporting requirements and started implementation of the software. While the Company continues to assess the impact on its accounting policies, internal control processes and related disclosures required under the new guidance, as well as its process to determine the actual amount of the required transition adjustment to reflect the balance of the right of use asset and lease liability, the Company’s current estimate of the initial lease liability based on the status of its adoption processes is approximately $100,000 and is subject to change as the Company continues to refine this amount. These conclusions may change as the Company continues to evaluate the new standard or if there are any changes in the Company’s lease portfolio. The Company does not currently believe that the standard will have a material impact on its results of operations or cash flows.

In June 2016, the FASB, issued ASU No. 2016-13, “Financial Instruments - Credit Losses (Topic 326)”: Measurement of Credit Losses on Financial Instruments, which changes the recognition model for the impairment of financial instruments, including

accounts receivable, loans and held-to-maturity debt securities, among others. The guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. In contrast to current guidance, which considers current information and events and utilizes a probable threshold, (an “incurred loss” model), ASU 2016–13 mandates an “expected loss” model. The expected loss model: (i) estimates the risk of loss even when risk is remote, (ii) estimates losses over the contractual life, (iii) considers past events, current conditions and reasonable supported forecasts and (iv) has no recognition threshold. The Company is currently assessing the potential impact that the adoption will have on its consolidated financial statements.

In August 2017, the FASB issued ASU No. 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities”, which amends and simplifies existing guidance in order to allow companies to more accurately present the economic effects of risk management activities in the financial statements. The guidance eliminates the requirement to separately measure and report hedge ineffectiveness and generally requires the entire change in the fair value of a hedging instrument to be presented in the same income statement line as the hedged item. The guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those years. Early adoption is permitted in any interim period or fiscal year before the effective date. The Company is currently assessing the potential impact that the adoption will have on its consolidated financial statements and does not believe that it will have a material impact on its consolidated financial statements.

In February 2018, the FASB issued ASU No. 2018-02, “Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income”, which allows a reclassification from accumulated other comprehensive income (loss) to retained earnings for stranded tax effects resulting from the Tax Act. The amount of the reclassification is calculated based on the effect of the change in the U.S. federal corporate income tax rate on the gross deferred tax amounts at the date of the enactment of the Tax Act related to items that remained in accumulated other comprehensive income (loss) at that time. The guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those years and early adoption is permitted. The Company is currently assessing the potential impact that the adoption will have on its consolidated financial statements.

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.

Acquisitions

12 Months Ended

Mar. 31, 2019

Acquisitions

On December 7, 2018, the Company completed the acquisition of all of the issued and outstanding common stock of Alpha Technologies Services, Inc. (“ATS”) and Alpha Technologies Ltd. (“ATL”), resulting in ATS and ATL becoming wholly-owned subsidiaries of the Company (the “share purchase”). Additionally, the Company acquired substantially all of the assets of Alpha Technologies Inc. and certain assets of Altair Advanced Industries, Inc. and other affiliates of ATS and ATL (all such sellers, together with ATS and ATL, “Alpha”), in each case in accordance with the terms and conditions of certain restructuring agreements (collectively, the “asset acquisition” and together with the share purchase, the “acquisition”). Based in Bellingham, Washington, Alpha is a global industry leader in comprehensive commercial-grade energy solutions for broadband, telecom, renewable, industrial and traffic customers around the world. The initial purchase consideration for the acquisition was $750,000, of which $650,000 was paid in cash and the balance was settled by issuing 1,177,630 shares of EnerSys common stock. These shares were issued out of the Company's treasury stock and were valued at $84.92 per share, which was based on the thirty-day volume weighted average stock price of the Company’s common stock at closing, in accordance with the purchase agreement. The 1,177,630 shares had a closing date fair value of $93,268, based upon the December 7, 2018, closing date spot rate of $79.20. The total purchase consideration, consisting of cash paid of $650,000, shares valued at $93,268 and an adjustment for working capital (due from seller of $766) was $742,502. The Company funded the cash portion of the acquisition with borrowings from the Amended Credit Facility as defined in Note 8. See Note 8 for additional information.

The acquisition expands the Company's footprint in broadband and telecom markets. The goodwill recognized in connection with this transaction reflects the benefits the Company expects to realize from being able to provide a one-stop, fully integrated power solutions offering to its customers, as well as the benefit of cost synergies from alignment of the Alpha group within its own organizational structure.

The Company recorded the acquisition using the acquisition method of accounting and recognized the assets acquired and liabilities assumed at their estimated fair values as of the date of the acquisition. The results of operations of Alpha have been included in the Company’s Americas segment beginning December 8, 2018. Included within operating expenses, in the Company's Consolidated Statement of Income for fiscal 2019 are acquisition costs of $12,883.

For the period ended March 31, 2019, that EnerSys owned Alpha, the contribution of the acquisition to net sales was $162,454 and net loss of $1,252, excluding the effect of the transaction and integration costs, and interest expense on the debt to finance the acquisition.

The following table represents the fair values assigned to the assets acquired and liabilities assumed and resulting goodwill. The amounts recognized will be finalized as the information necessary to complete the analysis is obtained, but no later than one year from the acquisition date (“the measurement period”).

The acquired assets and assumed liabilities include the following:



Accounts receivable	$	115,467
Inventories	84,297
Other current assets	6,822
Other intangible assets	332,000
Property, plant and equipment	20,987
Other assets	9,005
Total assets acquired	$	568,578
Accounts payable	35,803
Accrued liabilities	41,918
Deferred income taxes	56,331
Other liabilities	12,642
Total liabilities assumed	$	146,694
Net assets acquired	$	421,884

Purchase price:
Cash paid for net assets acquired	$	650,000
Fair value of shares issued for net assets acquired	93,268
Working capital adjustment	(766		)
Total purchase consideration	742,502
Less: Fair value of acquired identifiable assets and liabilities	421,884
Goodwill	$	320,618

The following table summarizes the estimated fair value of Alpha's identifiable intangible assets and the initial assessment of their respective estimated lives:



	Type	Life in Years	Fair Value
Trademarks	Indefinite-lived	Indefinite	$	56,000
Customer relationships	Finite-lived	14	221,000
Technology	Finite-lived	10	55,000
Total identifiable intangible assets			$	332,000

The Company recorded the acquisition using the acquisition method of accounting and recognized the assets acquired and liabilities assumed at their fair values as of the date of the acquisition. The excess of the purchase price over the net tangible and intangible assets is recorded to goodwill. Estimated goodwill deductible for tax purposes is $42,262. The measurement of the fair value of assets acquired and liabilities assumed is substantially complete. The Company continues to gather necessary information to finalize the accounting for income taxes associated with the acquisition, and as such the Company could record additional adjustments to the provisional amount recognized as this additional information is obtained.

The following unaudited summary information is presented on a consolidated pro forma basis as if the acquisition had occurred on April 1, 2017:



	Fiscal year ended
	March 31, 2019		March 31, 2018
Net sales	$	3,278,646	$	3,124,527
Net earnings attributable to EnerSys stockholders	207,904		126,965
Net earnings per share attributable to EnerSys stockholders - basic	4.79		2.90
Net earnings per share attributable to EnerSys stockholders - assuming dilution	4.71		2.87

The pro forma amounts include additional interest expense on the debt issued to finance the purchases, amortization and depreciation expense based on the estimated fair value and useful lives of intangible assets and plant assets, and related tax effects. The pro forma results are not necessarily indicative of the combined results had the Alpha acquisition been completed on April 1, 2017, nor are they indicative of future combined results. The pro forma results for the twelve months of fiscal 2019 and 2018 exclude pre-tax transaction costs of $12,883, as well as the pre-tax amortization of the acquisition date step up to fair value of inventories of $7,263 as they are considered non-recurring in nature. The remeasurement of Alpha's deferred taxes due to the Tax Act are also being excluded in arriving at these pro forma results.

The Company made no significant acquisitions in fiscal 2018 and 2017.

Inventories

12 Months Ended

Mar. 31, 2019



	March 31,
	2019		2018
Raw materials	$	138,718	$	92,216
Work-in-process	129,736		136,068
Finished goods	235,415		185,950
Total	$	503,869	$	414,234

Property, Plant, and Equipment

12 Months Ended

Mar. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Property, plant, and equipment consist of:



	March 31,
	2019			2018
Land, buildings, and improvements	$	268,006		$	273,506
Machinery and equipment	683,955			657,262
Construction in progress	54,278			49,900
	1,006,239			980,668
Less accumulated depreciation	(596,800		)	(590,408		)
Total	$	409,439		$	390,260

Depreciation expense for the fiscal years ended March 31, 2019, 2018 and 2017 totaled $48,618, $45,874, and $45,388, respectively. Interest capitalized in connection with major capital expenditures amounted to $1,581, $1,082, and $817 for the fiscal years ended March 31, 2019, 2018 and 2017, respectively.

Goodwill and Other Intangible Assets

12 Months Ended

Mar. 31, 2019

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Other Intangible Assets

Information regarding the Company’s other intangible assets are as follows:



	March 31,
	2019							2018
	Gross Amount		Accumulated Amortization			Net Amount		Gross Amount		Accumulated Amortization			Net Amount
Indefinite-lived intangible assets:
Trademarks	$	152,484	$	(953	)	$	151,531	$	97,444	$	(953	)	$	96,491
Finite-lived intangible assets:
Customer relationships	286,664		(42,704		)	243,960		66,973		(31,500		)	35,473
Non-compete	3,025		(2,807		)	218		2,852		(2,759		)	93
Technology	77,779		(12,229		)	65,550		22,769		(8,872		)	13,897
Trademarks	2,003		(1,236		)	767		2,003		(1,151		)	852
Licenses	1,477		(1,187		)	290		1,491		(1,156		)	335
Total	$	523,432	$	(61,116	)	$	462,316	$	193,532	$	(46,391	)	$	147,141

The Company’s amortization expense related to finite-lived intangible assets was $14,730, $8,443, and $8,557, for the years ended March 31, 2019, 2018 and 2017, respectively. The expected amortization expense based on the finite-lived intangible assets as of March 31, 2019, is $29,491 in fiscal 2020, $29,237 in fiscal 2021, $28,993 in fiscal 2022, $27,694 in fiscal 2023 and $24,287 in fiscal 2024.

Goodwill

The changes in the carrying amount of goodwill by reportable segment are as follows:



	Fiscal year ended March 31, 2019
	Americas			EMEA			Asia			Total
Balance at beginning of year	$	151,255		$	155,825		$	45,725		$	352,805
Acquisitions during the year	320,618			—			—			320,618
Foreign currency translation adjustment	(1,679		)	(12,556		)	(2,789		)	(17,024		)
Balance at end of year	$	470,194		$	143,269		$	42,936		$	656,399



	Fiscal year ended March 31, 2018
	Americas		EMEA		Asia		Total
Balance at beginning of year	$	146,982	$	138,813	$	42,862	$	328,657
Acquisitions during the year	3,670		—		—		3,670
Foreign currency translation adjustment	603		17,012		2,863		20,478
Balance at end of year	$	151,255	$	155,825	$	45,725	$	352,805

A reconciliation of goodwill and accumulated goodwill impairment losses, by reportable segment, is as follows:



	March 31, 2019
	Americas			EMEA			Asia			Total
Gross carrying value	$	528,039		$	149,422		$	48,115		$	725,576
Accumulated goodwill impairment charges	(57,845		)	(6,153		)	(5,179		)	(69,177		)
Net book value	$	470,194		$	143,269		$	42,936		$	656,399



	March 31, 2018
	Americas			EMEA			Asia			Total
Gross carrying value	$	209,100		$	161,978		$	50,904		$	421,982
Accumulated goodwill impairment charges	(57,845		)	(6,153		)	(5,179		)	(69,177		)
Net book value	$	151,255		$	155,825		$	45,725		$	352,805

Impairment of goodwill and indefinite-lived intangibles

The Company did not record any impairment relating to its goodwill and intangible assets during fiscal 2019 and 2018.

In fiscal 2017, the Company early adopted ASU 2017-04 - Intangibles—Goodwill and Other (Topic 350), which eliminated Step 2 from the goodwill impairment test. In the fourth quarter of fiscal 2017, the Company conducted step one of the annual goodwill impairment test which indicated that the fair values of two of its reporting units - Purcell US in the Americas operating segment and Purcell EMEA in the EMEA operating segment - were less than their respective carrying values. Based on the guidance in ASU 2017-04, the Company recognized an impairment charge for the amount by which the carrying amount exceeded the reporting unit’s fair value and recorded a non-cash charge of $8,646 and $3,570, related to goodwill impairment in the Americas and EMEA operating segments, respectively, and $700 and $1,100 related to impairment of indefinite-lived trademarks in the Americas and EMEA operating segments, respectively.

Purcell was acquired in fiscal 2014 during the height of the 4G telecom build-out. After performing to expectations for the first few quarters, its revenue declined as telecom spending in the U.S. curtailed sharply. In fiscal 2016, lower estimated projected revenue and profitability caused by reduced levels of capital spending by major customers in the telecommunications industry was a key factor contributing to the impairment charges recorded in that year. In fiscal 2017, the Company transferred the European operations of Purcell to its EMEA operating segment, consistent with its geographical management approach. In the U.S., Purcell received significant orders, but at lower margins, resulting in an impairment in 2017. In Europe, Purcell's sales forecasts were reduced in fiscal 2017, as a result of low telecom spending and accordingly recorded an impairment charge as well.

The Company estimated tax-deductible goodwill to be approximately $58,699 and $18,147 as of March 31, 2019 and 2018, respectively.

Prepaid and Other Current Assets

12 Months Ended

Mar. 31, 2019

Prepaid and Other Current Assets

Prepaid and other current assets consist of the following:



	March 31,
	2019		2018
Contract assets	$	38,778	$	—
Prepaid non-income taxes	22,490		22,583
Non-trade receivables	10,823		4,087
Prepaid income taxes	9,608		8,921
Other	27,732		21,319
Total	$	109,431	$	56,910

Accrued Expenses

12 Months Ended

Mar. 31, 2019

Accrued Expenses

Accrued expenses consist of the following:



	March 31,
	2019		2018
Payroll and benefits	$	54,285	$	50,053
Accrued selling expenses	35,394		34,831
Warranty	21,646		22,637
VAT and other non-income taxes	17,125		13,155
Project related accruals	16,301		—
Contract liabilities	15,162		—
Freight	14,423		15,810
Income taxes payable	9,234		19,696
Legal proceedings	7,258		2,326
Interest	7,248		6,762
Tax Act - Transition Tax	5,290		7,800
Restructuring	2,952		2,909
Pension	1,207		1,657
Deferred income	—		9,387
Other	48,356		27,095
Total	$	255,881	$	214,118

Debt

12 Months Ended

Mar. 31, 2019

Debt

The following summarizes the Company’s long-term debt:



	As of March 31,
	2019				2018
	Principal		Unamortized Issuance Costs		Principal		Unamortized Issuance Costs
5.00% Senior Notes, due 2023	$	300,000	$	2,497	$	300,000	$	3,122
Amended Credit Facility, due 2022^*	677,315		3,062		285,500		2,843
	$	977,315	$	5,559	$	585,500	$	5,965
Less: Unamortized issuance costs	5,559				5,965
Less: Current portion	—				—
Long-term debt, net of unamortized issuance costs	$	971,756			$	579,535

* As of March 31, 2018, the 2017 Credit Facility, due 2022

5.00% Senior Notes

The Company's $300,000 5.00% Senior Notes due 2023 (the “Notes”) bear interest at a rate of 5.00% per annum. Interest is payable semiannually in arrears on April 30 and October 30 of each year, and commenced on October 30, 2015. The Notes will mature on April 30, 2023, unless earlier redeemed or repurchased in full. The Notes are unsecured and unsubordinated obligations of the Company. The Notes are fully and unconditionally guaranteed (the “Guarantees”), jointly and severally, by certain of its subsidiaries that are guarantors (the “Guarantors”) under the Amended Credit Facility. The Guarantees are unsecured and unsubordinated obligations of the Guarantors.

2017 Credit Facility and Subsequent Amendment

On August 4, 2017, the Company entered into a credit facility (the “2017 Credit Facility”). The 2017 Credit Facility with a maturity date of September 30, 2022 consisted of a $600,000 senior secured revolving credit facility (“2017 Revolver”) and a $150,000 senior secured term loan (“2017 Term Loan”). The Company's previous credit facility (“2011 Credit Facility”)

consisted of a $500,000 senior secured revolving credit facility (“2011 Revolver”) and a $150,000 senior secured incremental term loan (the “2011 Term Loan”) with a maturity date of September 30, 2018. On August 4, 2017, the outstanding balance on the 2011 Revolver and the 2011 Term Loan of $240,000 and $123,750, respectively, was repaid utilizing borrowings from the 2017 Credit Facility.

On December 7, 2018, the Company amended the 2017 Credit Facility (as amended, the “Amended Credit Facility”) to fund the Alpha acquisition. The Amended Credit Facility consists of $449,105 senior secured term loans (the “Amended 2017 Term Loan”), including a CAD 133,050 ($99,105) term loan and a $700,000 senior secured revolving credit facility (the “Amended 2017 Revolver”). The amendment resulted in an increase of the 2017 Term Loan and the 2017 Revolver by $299,105 and $100,000, respectively.

As of March 31, 2019, the Company had $239,000 outstanding on the Amended 2017 Revolver and $438,315 under the Amended 2017 Term Loan.

Subsequent to the amendment, the quarterly installments payable on the Amended 2017 Term Loan are $5,625 beginning December 31, 2018, $8,438 beginning December 31, 2019 and $11,250 beginning December 31, 2020 with a final payment of $315,000 on September 30, 2022. The Amended Credit Facility may be increased by an aggregate amount of $325,000 in revolving commitments and /or one or more new tranches of term loans, under certain conditions. Both the Amended 2017 Revolver and the Amended 2017 Term Loan bear interest, at the Company's option, at a rate per annum equal to either (i) the London Interbank Offered Rate (“LIBOR”) or Canadian Dollar Offered Rate (“CDOR”) plus between (i) LIBOR plus between 1.25% and 2.00% (currently 1.25% and based on the Company's consolidated net leverage ratio) or (ii) the U.S. Dollar Base Rate (which equals, for any day a fluctuating rate per annum equal to the highest of (a) the Federal Funds Effective Rate plus 0.50%, (b) Bank of America “Prime Rate” and (c) the Eurocurrency Base Rate plus 1%; provided that, if the Base Rate shall be less than zero, such rate shall be deemed zero) (iii) the CDOR Base Rate equal to the higher of (a) Bank of America “Prime Rate” and (b) average 30-day CDOR rate plus 0.50%. Obligations under the Amended Credit Facility are secured by substantially all of the Company’s existing and future acquired assets, including substantially all of the capital stock of the Company’s United States subsidiaries that are guarantors under the Amended Credit Facility and up to 65% of the capital stock of certain of the Company’s foreign subsidiaries that are owned by the Company’s United States subsidiaries.

The Amended Credit Facility allows for up to two temporary increases in the maximum leverage ratio from 3.50x to 4.00x for a four quarter period following an acquisition larger than $250,000. Effective December 7, 2018 through December 30, 2019, the maximum leverage ratio has been increased to 4.00x. As of March 31, 2019, the leverage ratio was 2.00x.

The current portion of the Amended 2017 Term Loan of $28,098 is classified as long-term debt as the Company expects to refinance the future quarterly payments with revolver borrowings under its Amended Credit Facility.

2011 Credit Facility

As discussed under the 2017 Credit Facility, the 2011 Credit Facility was repaid in full on August 4, 2017. There were no prepayment penalties on loans under the 2011 Credit Facility. Both the revolving loan and the Term Loan under the 2011 Credit Facility bore interest, at the Company's option, at a rate per annum equal to either (i) LIBOR plus between 1.25% and 1.75% (1.25% at March 31, 2017, and based on the Company's consolidated net leverage ratio) or (ii) the Base Rate (which is the highest of (a) the Bank of America prime rate, and (b) the Federal Funds Effective Rate) plus between 0.25% and 0.75% (based on the Company’s consolidated net leverage ratio).

Interest Rates on Long Term Debt

The weighted average interest rate on the long term debt at March 31, 2019 and March 31, 2018, was 4.1% and 3.7%, respectively.

Interest Paid

The Company paid in cash, $29,552, $23,527 and $20,781, net of interest received, for interest during the fiscal years ended March 31, 2019, 2018 and 2017, respectively.

Covenants

The Company’s financing agreements contain various covenants, which, absent prepayment in full of the indebtedness and other obligations, or the receipt of waivers, would limit the Company’s ability to conduct certain specified business transactions including incurring debt, mergers, consolidations or similar transactions, buying or selling assets out of the ordinary course of business, engaging in sale and leaseback transactions, paying dividends and certain other actions. The Company is in compliance with all such covenants.

Short-Term Debt

As of March 31, 2019 and 2018, the Company had $54,490 and $18,341, respectively, of short-term borrowings from banks. The weighted-average interest rate on these borrowings was approximately 4% and 7%, respectively, for fiscal years ended March 31, 2019 and 2018.

Letters of Credit

As of March 31, 2019 and 2018, the Company had $3,955 and $3,074, respectively, of standby letters of credit.

Debt Issuance Costs

In fiscal 2019, the Company incurred $1,393 in debt issuance costs and wrote off $483 of unamortized debt issuance costs related to the Amended Credit Facility. In fiscal 2018, the Company incurred $2,677 in debt issuance costs and wrote off $301 of unamortized debt issuance costs related to the 2011 Credit Facility. Amortization expense, relating to debt issuance costs, included in interest expense was $1,316, $1,302, and $1,388 for the fiscal years ended March 31, 2019, 2018 and 2017, respectively. Debt issuance costs, net of accumulated amortization, totaled $5,559 and $5,965 as of March 31, 2019 and 2018, respectively.

Available Lines of Credit

As of March 31, 2019 and 2018, the Company had available and undrawn, under all its lines of credit, $546,960 and $613,234, respectively, including $87,685 and $150,459, respectively, of uncommitted lines of credit as of March 31, 2019 and March 31, 2018.

Leases

12 Months Ended

Mar. 31, 2019

Leases

The Company’s future minimum lease payments under operating leases that have noncancelable terms in excess of one year as of March 31, 2019 are as follows:




2020	$	31,483
2021	24,290
2022	16,514
2023	11,596
2024	8,683
Thereafter	23,757
Total minimum lease payments	$	116,323

Rental expense was $40,261, $38,146, and $35,991 for the fiscal years ended March 31, 2019, 2018 and 2017, respectively. Certain operating lease agreements contain renewal or purchase options and / or escalation clauses.

Other Liabilities

12 Months Ended

Mar. 31, 2019

Other Liabilities

Other liabilities consist of the following:



	March 31,
	2019		2018
Tax Act - Transition Tax	$	55,489	$	89,700
Pension	39,924		44,404
Warranty	32,922		27,965
Liability for uncertain tax positions	20,240		1,684
Deferred income	—		7,094
Contract liabilities	6,360		—
Other	10,265		10,240
Total	$	165,200	$	181,087

Fair Value of Financial Instruments

12 Months Ended

Mar. 31, 2019

Recurring Fair Value Measurements

The following tables represent the financial assets and (liabilities) measured at fair value on a recurring basis as of March 31, 2019 and March 31, 2018 and the basis for that measurement:



	Total Fair Value Measurement March 31, 2019			Quoted Price in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Lead forward contracts	$	(902	)	$	—	$	(902	)	$	—
Foreign currency forward contracts	(249		)	—		(249		)	—
Total derivatives	$	(1,151	)	$	—	$	(1,151	)	$	—



	Total Fair Value Measurement March 31, 2018			Quoted Price in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Lead forward contracts	$	(3,877	)	$	—	$	(3,877	)	$	—
Foreign currency forward contracts	22			—		22			—
Total derivatives	$	(3,855	)	$	—	$	(3,855	)	$	—

The fair values of lead forward contracts are calculated using observable prices for lead as quoted on the London Metal Exchange (“LME”) and, therefore, were classified as Level 2 within the fair value hierarchy as described in Note 1, Summary of Significant Accounting Policies.

The fair values for foreign currency forward contracts are based upon current quoted market prices and are classified as Level 2 based on the nature of the underlying market in which these derivatives are traded.

Financial Instruments

The fair values of the Company’s cash and cash equivalents approximate carrying value due to their short maturities.

The fair value of the Company’s short-term debt and borrowings under the Amended Credit Facility (as defined in Note 8), approximate their respective carrying value, as they are variable rate debt and the terms are comparable to market terms as of the balance sheet dates and are classified as Level 2.

The Company's Notes, with an original face value of $300,000, were issued in April 2015. The fair value of the Notes represent the trading values based upon quoted market prices and are classified as Level 2. The Notes were trading at approximately 99% and 102% of face value on March 31, 2019 and March 31, 2018, respectively.

The carrying amounts and estimated fair values of the Company’s derivatives and Notes at March 31, 2019 and 2018 were as follows:



	March 31, 2019				March 31, 2018
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Financial assets:
Derivatives⁽¹⁾	$	—	$	—	$	22	$	22
Financial liabilities:
Notes ⁽²⁾	300,000		297,000		300,000		304,500
Derivatives⁽¹⁾	$	1,151	$	1,151	$	3,877	$	3,877


(1)	Represents lead and foreign currency forward contracts (see Note 12 for asset and liability positions of the lead and foreign currency forward contracts at March 31, 2019 and March 31, 2018).


(2)	The fair value amount of the Notes at March 31, 2019 and March 31, 2018 represent the trading value of the instruments.

Non-recurring fair value measurements

On March 5, 2019, the Company committed to a plan to close its facility in Targovishte, Bulgaria, which produced diesel-electric submarine batteries. Management determined that the future demand for batteries of diesel-electric submarines was not sufficient given the number of competitors in the market. As a result, the Company concluded that the carrying value of the asset group is not recoverable and recorded a write-off of $14,958 in the fixed assets to their estimated fair value of $242, which was recognized in the fourth quarter of fiscal 2019. The valuation technique used to measure the fair value of fixed assets was a combination of the income and market approaches. The inputs used to measure the fair value of these fixed assets under the income approach were largely unobservable and accordingly were classified as Level 3.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivative Financial Instruments

12 Months Ended

Mar. 31, 2019

The Company utilizes derivative instruments to reduce its exposure to fluctuations in commodity prices and foreign exchange rates, under established procedures and controls. The Company does not enter into derivative contracts for speculative purposes. The Company’s agreements are with creditworthy financial institutions and the Company anticipates performance by counterparties to these contracts and therefore no material loss is expected.

Derivatives in Cash Flow Hedging Relationships

Lead Forward Contracts

The Company enters into lead forward contracts to fix the price for a portion of its lead purchases. Management considers the lead forward contracts to be effective against changes in the cash flows of the underlying lead purchases. The vast majority of such contracts are for a period not extending beyond one year. At March 31, 2019 and 2018, the Company has hedged the price to purchase approximately 42.0 million pounds and 62.9 million pounds of lead, respectively, for a total purchase price of $39,218 and $72,207, respectively.

Foreign Currency Forward Contracts

The Company uses foreign currency forward contracts and options to hedge a portion of the Company’s foreign currency exposures for lead, as well as other foreign currency exposures so that gains and losses on these contracts offset changes in the underlying foreign currency denominated exposures. The vast majority of such contracts are for a period not extending beyond one year. As of March 31, 2019 and 2018, the notional amount of these contracts was $42,318 and $54,164, respectively.

In the coming twelve months, the Company anticipates that $46 of pretax loss relating to lead and foreign currency forward contracts will be reclassified from AOCI as part of Cost of goods sold. This amount represents the current net unrealized impact of hedging lead and foreign exchange rates, which will change as market rates change in the future, and will ultimately be

realized in the Consolidated Statements of Income as an offset to the corresponding actual changes in lead costs to be realized in connection with the variable lead cost and foreign exchange rates being hedged.

Derivatives not Designated in Hedging Relationships

Foreign Currency Forward Contracts

The Company also enters into foreign currency forward contracts to economically hedge foreign currency fluctuations on intercompany loans and foreign currency denominated receivables and payables. These are not designated as hedging instruments and changes in fair value of these instruments are recorded directly in the Consolidated Statements of Income. As of March 31, 2019 and 2018, the notional amount of these contracts was $22,201 and $28,486, respectively.

Presented below in tabular form is information on the location and amounts of derivative fair values in the Consolidated Balance Sheets and derivative gains and losses in the Consolidated Statements of Income:

Fair Value of Derivative Instruments

March 31, 2019 and 2018



	Derivatives and Hedging Activities Designated as Cash Flow Hedges				Derivatives and Hedging Activities Not Designated as Hedging Instruments
	March 31, 2019		March 31, 2018		March 31, 2019		March 31, 2018
Prepaid and other current assets:
Foreign currency forward contracts	—		209		—		—
Total assets	$	—	$	209	$	—	$	—
Accrued expenses:
Lead forward contracts	$	902	$	3,877	$	—	$	—
Foreign currency forward contracts	8		—		241		187
Total liabilities	$	910	$	3,877	$	241	$	187

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ended March 31, 2019



Derivatives Designated as Cash Flow Hedges	Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Lead forward contracts	$	(12,531	)	Cost of goods sold	$	(15,666	)
Foreign currency forward contracts	1,551			Cost of goods sold	385
Total	$	(10,980	)		$	(15,281	)



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivatives	Pretax Gain (Loss)
Foreign currency forward contracts	Other (income) expense, net	$	(1,856	)
Total		$	(1,856	)

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ended March 31, 2018



Derivatives Designated as Cash Flow Hedges	Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Lead forward contracts	$	(805	)	Cost of goods sold	$	5,860
Foreign currency forward contracts	(3,524		)	Cost of goods sold	(2,718		)
Total	$	(4,329	)		$	3,142



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivatives	Pretax Gain (Loss)
Foreign currency forward contracts	Other (income) expense, net	$	180
Total		$	180

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ended March 31, 2017



Derivatives Designated as Cash Flow Hedges	Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)		Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Lead forward contracts	$	7,907	Cost of goods sold	$	5,803
Foreign currency forward contracts	845		Cost of goods sold	433
Total	$	8,752		$	6,236



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivatives	Pretax Gain (Loss)
Foreign currency forward contracts	Other (income) expense, net	$	(471	)
Total		$	(471	)

Income Taxes

12 Months Ended

Mar. 31, 2019



	Fiscal year ended March 31,
	2019			2018			2017
Current income tax expense
Current:
Federal	$	6,377		$	115,315		$	30,362
State	5,027			3,461			4,855
Foreign	16,636			20,030			17,800
Total current income tax expense	28,040			138,806			53,017
Deferred income tax (benefit) expense
Federal	(5,031		)	(9,551		)	857
State	(669		)	789			590
Foreign	(756		)	(11,551		)	8
Total deferred income tax (benefit) expense	(6,456		)	(20,313		)	1,455
Total income tax expense	$	21,584		$	118,493		$	54,472

Earnings before income taxes consists of the following:



	Fiscal year ended March 31,
	2019		2018		2017
United States	$	53,339	$	74,440	$	80,436
Foreign	128,872		163,886		132,259
Earnings before income taxes	$	182,211	$	238,326	$	212,695

Income taxes paid by the Company for the fiscal years ended March 31, 2019, 2018 and 2017 were $53,866, $28,044 and $45,332, respectively.

U.S. Tax Cuts and Jobs Act of 2017

On December 22, 2017, the Tax Cuts and Jobs Act (“Tax Act”) was enacted into law. Among the significant changes resulting from the law, the Tax Act reduced the U.S. federal income tax rate from 35% to 21% effective January 1, 2018, and required companies to pay a one-time transition tax on unrepatriated cumulative non-U.S. earnings of foreign subsidiaries and created new taxes on certain foreign sourced earnings. The U.S. federal statutory tax rate for fiscal 2019 is 21.0%.

On December 22, 2017, the SEC issued Staff Accounting Bulletin No. 118 (“SAB 118”) that provided guidance on the financial statement implications of the Tax Act. In fiscal 2018, the Company recorded a provisional amount for the Transition Tax liability, resulting in an increase in income tax expense of $97,500. In fiscal 2019, the Company completed its accounting for the tax effects of enactment of the Tax Act. The Company recognized an income tax benefit of $13,483, net of uncertain tax positions, resulting from a decrease in the mandatory one-time transition tax on unrepatriated cumulative non-U.S. earnings of the Company's foreign businesses. The Company made the election on the 2017 Federal Income Tax Return to pay the one-time Tax Act liability over an eight-year period without interest, as allowed under the tax enactment.

In fiscal 2019, the global intangible low-taxed income (“GILTI”), foreign derived intangible income (“FDII”), and base-erosion and anti-abuse (“BEAT”) provisions became effective. The GILTI provisions require the Company to include in its US income tax return foreign subsidiary earnings in excess of an allowable return on the foreign subsidiary’s tangible assets. Under US GAAP, the Company is allowed to make an accounting policy choice of either (1) treating the taxes due on future US inclusions in taxable income as a current-period expense when incurred (“period cost method”) or (2) factoring amounts into a Company’s measurement of its deferred taxes (“deferred method”). The Company has elected the period cost method. Based on existing legislative guidance and interpretation, the Company's effective tax rate has increased by approximately 2.2% compared to prior year.

FDII allows a new deduction for U.S. corporations up to 37.5% of foreign derived intangible income. This is an export incentive that reduces the tax on foreign derived sales and service income. Based upon the existing legislative guidance and interpretation, the Company's effective tax rate has decreased by 0.9% compared to prior year.

The BEAT provisions eliminate the deductions of certain base-erosion payments to related foreign corporations and impose a minimum tax if greater than regular tax. The Company does not expect to be subject to BEAT for fiscal 2019.

The following table sets forth the tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities:



	March 31,
	2019			2018
Deferred tax assets:
Accounts receivable	$	1,297		$	1,790
Inventories	4,081			3,660
Net operating loss carryforwards	48,423			50,928
Accrued expenses	21,574			21,274
Capitalized research and development costs	7,061			—
Other assets	17,656			16,832
Gross deferred tax assets	100,092			94,484
Less valuation allowance	(17,519		)	(15,255		)
Total deferred tax assets	82,573			79,229
Deferred tax liabilities:
Property, plant and equipment	25,656			21,045
Intangible assets	96,826			46,058
Other liabilities	1,737			1,331
Total deferred tax liabilities	124,219			68,434
Net deferred tax (liabilities) assets	$	(41,646	)	$	10,795

The Company has approximately $1,438 in United States federal net operating loss carryforwards, all of which are limited by Section 382 of the Internal Revenue Code, with expirations between 2023 and 2027. The Company has approximately $168,906 of foreign net operating loss carryforwards, of which $102,792 may be carried forward indefinitely and $66,114 expire between fiscal 2020 and fiscal 2034. In addition, the Company also has approximately $33,900 of state net operating loss carryforwards with expirations between fiscal 2020 and fiscal 2039.

As of March 31, 2019 and 2018, the federal valuation allowance was $1,027 and $630, respectively. Of the net increase of $397, $1,027 is due to the current year acquisition of Alpha, offset by $630 due to the expiration of capital losses for which a full valuation allowance was previously recorded. As of March 31, 2019 and 2018, the valuation allowance associated with the state tax jurisdictions was $898 and $895, respectively. As of March 31, 2019 and 2018, the valuation allowance associated with certain foreign tax jurisdictions was $15,594 and $13,730, respectively. Of the net increase of $1,864, $2,876 was recorded as an increase to tax expense primarily related to net operating loss carryforwards generated in the current year that the Company believes are not more likely than not to be realized. The remaining net decrease of $1,012 is primarily related to foreign currency translation adjustments and an offset to adjustments to foreign net operating losses for which a full valuation allowance was recorded.

A reconciliation of income taxes at the statutory rate (21.0% for fiscal 2019, 31.55% for fiscal 2018 and 35% for fiscal 2017) to the income tax provision is as follows:



	Fiscal year ended March 31,
	2019			2018			2017
United States statutory income tax expense	$	38,264		$	75,196		$	74,444
Increase (decrease) resulting from:
Impact of Tax Act	(13,483		)	83,400			—
State income taxes, net of federal effect	3,285			3,146			3,677
Nondeductible expenses, domestic manufacturing deduction (fiscal 2018 and 2017) and other	2,677			1,078			1,993
Legal proceedings charge - European Competition Investigations - See Note 18	2,405			—			7,873
Net effect of GILTI, FDII, BEAT	2,320			—			—
Goodwill impairment - See Note 5	—			—			3,812
Effect of foreign operations	(16,763		)	(35,048		)	(39,377		)
Valuation allowance	2,879			(9,279		)	2,050
Income tax expense	$	21,584		$	118,493		$	54,472

The effective income tax rates for the fiscal years ended March 31, 2019, 2018 and 2017 were 11.9%, 49.7% and 25.6%, respectively. The effective income tax rate with respect to any period may be volatile based on the mix of income in the tax jurisdictions in which the Company operates and the amount of its consolidated income before taxes. The rate decrease in fiscal 2019 compared to fiscal 2018 is primarily due to the impact of the Tax Act, partially offset by increases for additional tax valuation allowances related to certain of our foreign subsidiaries, increases due to non-deductible legal proceedings charge related to the European competition investigation, and changes in the mix of earnings among tax jurisdictions in fiscal 2019. The rate increase in fiscal 2018 compared to fiscal 2017 is also primarily due to the Tax Act.

In fiscal 2019, the foreign effective income tax rate on foreign pre-tax income of $128,872 was 12.3%. In fiscal 2018, the foreign effective income tax rate on foreign pre-tax income of $163,886 was 5.2% and in fiscal 2017, the foreign effective income tax rate on foreign pre-tax income of $132,259 was 13.5%. The rate increase in fiscal 2019 compared to fiscal 2018 is primarily due to additional tax valuation allowances related to certain of the Company’s foreign subsidiaries, increases due to non-deductible legal proceedings charge related to the European competition investigation, and changes in the mix of earnings among tax jurisdictions in fiscal 2019. The rate decrease in fiscal 2018 compared to fiscal 2017 is primarily due to the reversal of previously recognized deferred tax valuation allowances related to certain of the Company’s foreign subsidiaries in fiscal 2018, decreases due to non-deductible goodwill impairment charges and non-deductible legal proceedings charge related to the European competition investigation in fiscal 2017, and changes in the mix of earnings among tax jurisdictions.

Income from the Company's Swiss subsidiary comprised a substantial portion of its overall foreign mix of income for the fiscal years ended March 31, 2019, 2018 and 2017 and was taxed at approximately 4%, 8% and 5%, respectively.

The Company has approximately $1,167,000 and $1,260,000 of undistributed earnings of foreign subsidiaries for fiscal years 2019 and 2018, respectively. Since the Company’s undistributed foreign earnings and outside basis differences inherent in foreign entities continue to be indefinitely reinvested in foreign operations, no additional income taxes have been provided.

Uncertain Tax Positions

The following table summarizes activity of the total amounts of unrecognized tax benefits:



	Fiscal year ended March 31,
	2019			2018			2017
Balance at beginning of year	$	1,568		$	1,450		$	2,375
Increases related to current year tax positions	129			397			252
Increases related to the Alpha acquisition	7,840			—			—
Increases related to prior year tax positions	11,463			11			31
Decreases related to prior tax positions and foreign currency translation	(544		)	—			(352		)
Decreases related to prior year tax positions settled	(93		)	(1		)	(678		)
Lapse of statute of limitations	(198		)	(289		)	(178		)
Balance at end of year	$	20,165		$	1,568		$	1,450

The increase of prior year tax positions during fiscal 2019, are related to items included in the Tax Act. In connection with the Alpha acquisition, the Company recorded an unrecognized tax benefit of $7,840, as well as an indemnification asset of $7,840 representing the Seller's obligation to indemnify the Company for the outcome of potential contingent liabilities relating to uncertain tax positions. See Note 2 for more information relating to the acquisition.

All of the balance of unrecognized tax benefits at March 31, 2019, if recognized, would be included in the Company’s Consolidated Statements of Income and have a favorable impact on both the Company’s net earnings and effective tax rate.

The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction, and various states and foreign jurisdictions. With few exceptions, the Company is no longer subject to U.S. federal, state and local, or non-U.S. income tax examinations by tax authorities for years before 2008.

While the net effect on total unrecognized tax benefits cannot be reasonably estimated, approximately $2,275 is expected to reverse in fiscal 2020 due to expiration of various statute of limitations.

The Company recognizes tax related interest and penalties in income tax expense in its Consolidated Statements of Income. As of March 31, 2019 and 2018, the Company had an accrual of $75 and $116, respectively, for interest and penalties.

Retirement Plans

12 Months Ended

Mar. 31, 2019

Stockholders' Equity and Noncontrolling Interests [Abstract]

Retirement Plans

Defined Benefit Plans

The Company sponsors several retirement and pension plans covering eligible salaried and hourly employees. The Company uses a measurement date of March 31 for its pension plans.

Net periodic pension cost for fiscal 2019, 2018 and 2017, includes the following components:



	United States Plans									International Plans
	Fiscal year ended March 31,									Fiscal year ended March 31,
	2019			2018			2017			2019			2018			2017
Service cost	$	—		$	—		$	371		$	997		$	1,025		$	871
Interest cost	631			658			664			1,831			1,795			1,848
Expected return on plan assets	(514		)	(496		)	(816		)	(2,151		)	(2,264		)	(1,875		)
Amortization and deferral	184			303			453			1,520			1,468			978
Net periodic benefit cost	$	301		$	465		$	672		$	2,197		$	2,024		$	1,822

The following table sets forth a reconciliation of the related benefit obligation, plan assets, and accrued benefit costs related to the pension benefits provided by the Company for those employees covered by defined benefit plans:



	United States Plans						International Plans
	March 31,						March 31,
	2019			2018			2019			2018
Change in projected benefit obligation
Benefit obligation at the beginning of the period	$	16,713		$	16,682		$	82,033		$	74,478
Service cost	—			—			997			1,025
Interest cost	631			658			1,831			1,795
Benefits paid, inclusive of plan expenses	(1,061		)	(1,037		)	(1,758		)	(2,153		)
Plan curtailments and settlements	—			—			(1,130		)	(52		)
Actuarial losses (gains)	364			410			(261		)	(2,705		)
Foreign currency translation adjustment	—			—			(6,674		)	9,645
Benefit obligation at the end of the period	$	16,647		$	16,713		$	75,038		$	82,033



Change in plan assets
Fair value of plan assets at the beginning of the period	$	13,928		$	12,731		$	38,757		$	34,323
Actual return on plan assets	758			1,731			2,109			688
Employer contributions	138			503			1,670			1,865
Benefits paid, inclusive of plan expenses	(1,061		)	(1,037		)	(1,758		)	(2,153		)
Plan curtailments and settlements	—			—			(1,130		)	(52		)
Foreign currency translation adjustment	—			—			(2,857		)	4,086
Fair value of plan assets at the end of the period	$	13,763		$	13,928		$	36,791		$	38,757
Funded status deficit	$	(2,884	)	$	(2,785	)	$	(38,247	)	$	(43,276	)



	March 31,
	2019			2018
Amounts recognized in the Consolidated Balance Sheets consist of:
Accrued expenses	(1,207		)	(1,657		)
Other liabilities	(39,924		)	(44,404		)
Total liabilities	$	(41,131	)	$	(46,061	)

The following table represents pension components (before tax) and related changes (before tax) recognized in AOCI for the Company’s pension plans for the years ended March 31, 2019, 2018 and 2017:



	Fiscal year ended March 31,
	2019			2018			2017
Amounts recorded in AOCI before taxes:
Prior service cost	$	(307	)	$	(385	)	$	(377	)
Net loss	(24,051		)	(27,762		)	(28,475		)
Net amount recognized	$	(24,358	)	$	(28,147	)	$	(28,852	)



	Fiscal year ended March 31,
	2019			2018			2017
Changes in plan assets and benefit obligations:
New prior service cost	$	—		$	—		$	—
Net loss (gain) arising during the year	(99		)	(1,953		)	5,485
Effect of exchange rates on amounts included in AOCI	(1,984		)	3,019			(2,275		)
Amounts recognized as a component of net periodic benefit costs:
Amortization of prior service cost	(45		)	(46		)	(42		)
Amortization or settlement recognition of net loss	(1,659		)	(1,725		)	(1,389		)
Total recognized in other comprehensive (income) loss	$	(3,787	)	$	(705	)	$	1,779

The amounts included in AOCI as of March 31, 2019 that are expected to be recognized as components of net periodic pension cost (before tax) during the next twelve months are as follows:



Prior service cost	$	(44	)
Net loss	(1,185		)
Net amount expected to be recognized	$	(1,229	)

The accumulated benefit obligation related to all defined benefit pension plans and information related to unfunded and underfunded defined benefit pension plans at the end of each year are as follows:



	United States Plans				International Plans
	March 31,				March 31,
	2019		2018		2019		2018
All defined benefit plans:
Accumulated benefit obligation	$	16,647	$	16,713	$	71,350	$	77,724
Unfunded defined benefit plans:
Projected benefit obligation	$	—	$	—	$	32,320	$	33,124
Accumulated benefit obligation	—		—		30,328		31,270
Defined benefit plans with a projected benefit obligation in excess of the fair value of plan assets:
Projected benefit obligation	$	16,647	$	16,713	$	75,038	$	82,033
Fair value of plan assets	13,763		13,928		36,791		38,757
Defined benefit plans with an accumulated benefit obligation in excess of the fair value of plan assets:
Projected benefit obligation	$	16,647	$	16,713	$	74,235	$	81,253
Accumulated benefit obligation	16,647		16,713		70,654		77,021
Fair value of plan assets	13,763		13,928		36,077		37,986

Assumptions

Significant assumptions used to determine the net periodic benefit cost for the U.S. and International plans were as follows:



	United States Plans						International Plans
	Fiscal year ended March 31,						Fiscal year ended March 31,
	2019		2018		2017		2019	2018	2017
Discount rate	3.9	%	4.1	%	3.9	%	1.4-3.3%	1.5-3.5%	1.8-3.7%
Expected return on plan assets	6.3		6.8		7.0		4.1-6.0	3.6-6.3	3.3-6.5
Rate of compensation increase	N/A		N/A		N/A		1.8-4.0	1.5-4.0	1.5-4.0

N/A = not applicable

Significant assumptions used to determine the projected benefit obligations for the U.S. and International plans were as follows:



	United States Plans				International Plans
	March 31,				March 31,
	2019		2018		2019	2018
Discount rate	3.8	%	3.9	%	1.0-2.7%	1.4-3.3%
Rate of compensation increase	N/A		N/A		2.0-4.0	1.8-4.0

N/A = not applicable

The United States plans do not include compensation in the formula for determining the pension benefit as it is based solely on years of service.

The expected long-term rate of return for the Company’s pension plan assets is based upon the target asset allocation and is determined using forward looking assumptions in the context of historical returns and volatilities for each asset class, as well as correlations among asset classes. The Company evaluates the rate of return assumptions for each of its plans on an annual basis.

Pension Plan Investment Strategy

The Company’s investment policy emphasizes a balanced approach to investing in securities of high quality and ready marketability. Investment flexibility is encouraged so as not to exclude opportunities available through a diversified investment strategy.

Equity investments are maintained within a target range of 40% - 75% of the total portfolio market value for the U.S. plans and with a target of approximately 65% for international plans. Investments in debt securities include issues of various maturities, and the average quality rating of bonds should be investment grade with a minimum quality rating of “B” at the time of purchase.

The Company periodically reviews the asset allocation of its portfolio. The proportion committed to equities, debt securities and cash and cash equivalents is a function of the values available in each category and risk considerations. The plan’s overall return will be compared to and is expected to meet or exceed established benchmark funds and returns over a three to five year period.

The objectives of the Company’s investment strategies are: (a) the achievement of a reasonable long-term rate of total return consistent with an emphasis on preservation of capital and purchasing power, (b) stability of annual returns through a portfolio that reflects a conservative mix of risk versus return, and (c) reflective of the Company’s willingness to forgo significantly above-average rewards in order to minimize above-average risks. These objectives may not be met each year but should be attained over a reasonable period of time.

The following table represents the Company's pension plan investments measured at fair value as of March 31, 2019 and 2018 and the basis for that measurement:



	March 31, 2019
	United States Plans								International Plans
	Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Asset category:
Cash and cash equivalents	$	1,080	$	1,080	$	—	$	—	$	83	$	83	$	—	$	—
Equity securities
US^(a)	8,275		8,275		—		—		—		—		—		—
International^(b)	—		—		—		—		23,875		—		23,875		—
Fixed income^(c)	4,408		4,408		—		—		12,833		—		12,833		—
Total	$	13,763	$	13,763	$	—	$	—	$	36,791	$	83	$	36,708	$	—



	March 31, 2018
	United States Plans								International Plans
	Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Asset category:
Cash and cash equivalents	$	891	$	891	$	—	$	—	$	49	$	49	$	—	$	—
Equity securities
US^(a)	9,864		9,864		—		—		—		—		—		—
International^(b)	—		—		—		—		25,768		—		25,768		—
Fixed income^(c)	3,173		3,173		—		—		12,940		—		12,940		—
Total	$	13,928	$	13,928	$	—	$	—	$	38,757	$	49	$	38,708	$	—

The fair values presented above were determined based on valuation techniques to measure fair value as discussed in Note 1.


(a)	US equities include companies that are well diversified by industry sector and equity style (i.e., growth and value strategies). Active and passive management strategies are employed. Investments are primarily in large capitalization stocks and, to a lesser extent, mid- and small-cap stocks.


(b)	International equities are invested in companies that are traded on exchanges outside the U.S. and are well diversified by industry sector, country and equity style. Active and passive strategies are employed. The vast majority of the investments are made in companies in developed markets with a small percentage in emerging markets.


(c)	Fixed income consists primarily of investment grade bonds from diversified industries.

The Company expects to make cash contributions of approximately $1,640 to its pension plans in fiscal 2020.

Estimated future benefit payments under the Company’s pension plans are as follows:




2020	$	2,713
2021	2,783
2022	3,072
2023	3,392
2024	3,536
Years 2025-2029	21,106

Defined Contribution Plan

The Company maintains defined contribution plans primarily in the U.S. and U.K. Eligible employees can contribute a portion of their pre-tax and / or after-tax income in accordance with plan guidelines and the Company will make contributions based on the employees’ eligible pay and /or will match a percentage of the employee contributions up to certain limits. Matching contributions charged to expense for the fiscal years ended March 31, 2019, 2018 and 2017 were $12,078, $8,931 and $7,447, respectively.

Stockholders' Equity and Noncontrolling Interests

12 Months Ended

Mar. 31, 2019

Stockholders' Equity and Noncontrolling Interests

Stockholders’ Equity and Noncontrolling Interests

Preferred Stock and Common Stock

The Company’s certificate of incorporation authorizes the issuance of up to 1,000,000 shares of preferred stock, par value $0.01 per share (“Preferred Stock”). At March 31, 2019 and 2018, no shares of Preferred Stock were issued or outstanding. The Board of Directors of the Company has the authority to specify the terms of any Preferred Stock at the time of issuance.

The following summarizes the change in the number of shares of common stock outstanding during fiscal years ended March 31, 2017, 2018 and 2019, respectively:




Shares outstanding as of March 31, 2016	43,189,502
Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes	258,034
Shares outstanding as of March 31, 2017	43,447,536
Purchase of treasury stock	(1,756,831	)
Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes	224,295
Shares outstanding as of March 31, 2018	41,915,000
Purchase of treasury stock	(726,347	)
Shares issued towards purchase consideration of Alpha acquisition	1,177,630
Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes	254,467
Shares outstanding as of March 31, 2019	42,620,750

Treasury Stock

In fiscal 2019, the Company purchased 726,347 shares of its common stock for $56,436 and in fiscal 2018, purchased 1,756,831 shares for $121,191. Of the shares purchased in fiscal 2018, 1,495,714 were acquired through an accelerated share repurchase program (“ASR”) for a total cash investment of $100,000 at an average price of $66.86. There were no repurchases of common stock during fiscal 2017. At March 31, 2019 and 2018, the Company held 12,227,773 and 12,680,105 shares as treasury stock, respectively.

Treasury Stock Reissuance

On December 7, 2018, the Company acquired Alpha. The initial purchase consideration for the acquisition was $750,000, of which $650,000 was paid in cash and the balance was settled by issuing 1,177,630 shares of EnerSys common stock. These shares were issued out of the Company's treasury stock and were valued at $84.92 per share, which was based on the thirty-day volume weighted average stock price of the Company’s common stock at closing. The 1,177,630 shares had a closing date fair value of $93,268. During fiscal 2019, the Company also issued 3,256 shares out of its treasury stock, valued at $62.55 per share, on LIFO basis, to participants under the Company's Employee Stock Purchase Plan.

Accumulated Other Comprehensive Income (“AOCI”)

The components of AOCI, net of tax, are as follows:



	Beginning Balance			Before Reclassifications			Amount Reclassified from AOCI			Ending Balance
March 31, 2019
Pension funded status adjustment	$	(22,503	)	$	339		$	1,373		$	(20,791	)
Net unrealized gain (loss) on derivative instruments	(3,425		)	(8,396		)	11,691			(130		)
Foreign currency translation adjustment	(15,789		)	(105,972		)	—			(121,761		)
Accumulated other comprehensive loss	$	(41,717	)	$	(114,029	)	$	13,064		$	(142,682	)
March 31, 2018
Pension funded status adjustment	$	(25,555	)	$	1,692		$	1,360		$	(22,503	)
Net unrealized gain (loss) on derivative instruments	1,975			(2,868		)	(2,532		)	(3,425		)
Foreign currency translation adjustment	(129,244		)	113,455			—			(15,789		)
Accumulated other comprehensive loss	$	(152,824	)	$	112,279		$	(1,172	)	$	(41,717	)
March 31, 2017
Pension funded status adjustment	$	(21,861	)	$	(4,659	)	$	965		$	(25,555	)
Net unrealized gain (loss) on derivative instruments	388			5,523			(3,936		)	1,975
Foreign currency translation adjustment	(75,876		)	(53,368		)	—			(129,244		)
Accumulated other comprehensive loss	$	(97,349	)	$	(52,504	)	$	(2,971	)	$	(152,824	)

The following table presents reclassifications from AOCI during the twelve months ended March 31, 2019:



Components of AOCI	Amounts Reclassified from AOCI			Location of (Gain) Loss Recognized on Income Statement
Derivatives in Cash Flow Hedging Relationships:
Net unrealized loss on derivative instruments	$	15,281		Cost of goods sold
Tax benefit	(3,590		)
Net unrealized loss on derivative instruments, net of tax	$	11,691

Defined benefit pension costs:
Prior service costs and deferrals	$	1,704		Net periodic benefit cost, included in other (income) expense, net - See Note 1 and 14
Tax benefit	(331		)
Net periodic benefit cost, net of tax	$	1,373

The following table presents reclassifications from AOCI during the twelve months ended March 31, 2018:



Components of AOCI	Amounts Reclassified from AOCI			Location of (Gain) Loss Recognized on Income Statement
Derivatives in Cash Flow Hedging Relationships:
Net unrealized gain on derivative instruments	$	(3,142	)	Cost of goods sold
Tax expense	610
Net unrealized gain on derivative instruments, net of tax	$	(2,532	)

Defined benefit pension costs:
Prior service costs and deferrals	$	1,771		Net periodic benefit cost, included in other (income) expense, net - See Note 1 and 14
Tax benefit	(411		)
Net periodic benefit cost, net of tax	$	1,360

The following table presents reclassifications from AOCI during the twelve months ended March 31, 2017:



Components of AOCI	Amounts Reclassified from AOCI			Location of (Gain) Loss Recognized on Income Statement
Derivatives in Cash Flow Hedging Relationships:
Net unrealized gain on derivative instruments	$	(6,236	)	Cost of goods sold
Tax expense	2,300
Net unrealized gain on derivative instruments, net of tax	$	(3,936	)

Defined benefit pension costs:
Prior service costs and deferrals	$	1,431		Net periodic benefit cost, included in other (income) expense, net - See Note 1 and 14
Tax benefit	(466		)
Net periodic benefit cost, net of tax	$	965

Redeemable Noncontrolling Interests

In fiscal 2017, the Company deconsolidated its joint venture in South Africa and the impact of this deconsolidation was reflected in the Consolidated Statements of Income.

The following demonstrates the change in redeemable noncontrolling interests during the fiscal year ended March 31, 2017:




Balance as of March 31, 2016	$	5,997
Net losses attributable to redeemable noncontrolling interests	(2,021		)
Deconsolidation of joint venture	(4,035		)
Foreign currency translation adjustment	59
Balance as of March 31, 2017	$	—

Stock-Based Compensation

12 Months Ended

Mar. 31, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation

As of March 31, 2019, the Company maintains the 2017 Equity Incentive Plan (“2017 EIP”). The 2017 EIP reserved 4,173,554 shares of common stock for the grant of various classes of nonqualified stock options, restricted stock units, market and performance condition-based share units and other forms of equity-based compensation. Shares subject to any awards that expire without being exercised or that are forfeited or settled in cash shall again be available for future grants of awards under

the 2017 EIP. Shares subject to stock option or stock appreciation right awards, that have been retained by the Company in payment or satisfaction of the exercise price and any applicable tax withholding obligation of such awards, shall not be available for future grant under the 2017 EIP.

As of March 31, 2019, 3,750,392 shares are available for future grants. The Company’s management equity incentive plans are intended to provide an incentive to employees and non-employee directors of the Company to remain in the service of the Company and to increase their interest in the success of the Company in order to promote the long-term interests of the Company. The plans seek to promote the highest level of performance by providing an economic interest in the long-term performance of the Company. The Company settles employee share-based compensation awards with newly issued shares.

Stock Options

During fiscal 2019, the Company granted to management and other key employees 192,700 non-qualified options that vest ratably over 3 years from the date of grant. Options expire 10 years from the date of grant.

The Company recognized stock-based compensation expense relating to stock options of $3,251, with a related tax benefit of $634 for fiscal 2019, stock-based compensation expense of $2,741 with a related tax benefit of $700 for fiscal 2018 and stock-based compensation of $1,705 with a related tax benefit of $457 for fiscal 2017.

For purposes of determining the fair value of stock options granted, the Company used a Black-Scholes Model with the following assumptions:



	2019		2018		2017
Risk-free interest rate	2.77	%	2.08	%	1.41	%
Dividend yield	0.93	%	0.84	%	1.22	%
Expected life (years)	6		6		6
Volatility	26.8	%	29.2	%	30.4	%

The following table summarizes the Company’s stock option activity in the years indicated:



	Number of Options		Weighted- Average Remaining Contract Term (Years)	Weighted- Average Exercise Price		Aggregate Intrinsic Value
Options outstanding as of March 31, 2016	210,297		8.5	$	67.54	$	218
Granted	242,068			57.60		—
Exercised	(263	)		18.25		12
Expired	(434	)		18.25		15
Options outstanding as of March 31, 2017	451,668		8.4	$	62.29	$	7,520
Granted	169,703			83.14		—
Exercised	(62,197	)		63.44		1,132
Forfeited	(11,495	)		70.22		75
Expired	(2,089	)		18.25		137
Options outstanding as of March 31, 2018	545,590		8.4	$	68.65	$	2,679
Granted	192,700			75.17		—
Exercised	(171,630	)		63.66		2,707
Forfeited	(11,754	)		75.17		—
Options outstanding as of March 31, 2019	554,906		8.0	$	72.31	$	1,040
Options exercisable as of March 31, 2019	186,823		6.9	$	69.34	$	452
Options vested and expected to vest, as of March 31, 2019	545,299		8.0	$	72.24	$	1,038

The following table summarizes information regarding stock options outstanding as of March 31, 2019:




Range of Exercise Prices	Number of Options	Weighted- Average Remaining Contractual Life (Years)	Weighted- Average Exercise Price
$55.00-$60.00	137,599	7.1	$	57.60
$65.01-$70.00	73,368	5.8	$	68.82
$75.01-$83.14	343,939	8.8	$	78.95
	554,906	8.0	$	72.31

Restricted Stock Units, Market and Performance-condition based Awards

Non-employee directors

In fiscal 2019, the Company granted to non-employee directors 35,065 deferred restricted stock units at the fair value of $46.30 per restricted stock unit at the date of grant. In fiscal 2018, such grants amounted to 33,408 restricted stock units at the fair value of $46.24 per restricted stock unit at the date of grant and in fiscal 2017, such grants amounted to 25,708 restricted stock units at the fair value of $69.97 per restricted stock unit at the date of grant. The awards vest immediately upon the date of grant and are settled in shares of common stock six months after termination of service as a director.

In fiscal 2019, the Company also granted to non-employee directors, 1,441 restricted stock units and in fiscal 2018 and 2017, granted 1,345 and 1,239 restricted stock units, respectively, at fair values of $75.32, $73.39 and $65.88, for fiscal 2018, 2017 and 2016, respectively, under the deferred compensation plan.

Employees

In fiscal 2019, the Company granted to management and other key employees 204,599 restricted stock units that vest ratably over four years from the date of grant, at the fair value of $75.17 per restricted stock unit, 45,883 performance condition-based share units (“PSU”) at the fair value of $68.48 and 36,646 market condition-based share units (“TSR”) at the fair value of $86.23 per unit at the date of grant. The PSUs and TSRs cliff vest three years from the date of grant.

In fiscal 2018, the Company granted to management and other key employees 161,229 restricted stock units that vest ratably over four years from the date of grant at the fair value of $83.14 per restricted stock unit and 60,187 TSRs at a weighted average fair value of $105.74 per unit at the date of grant that cliff vest three years from the date of grant.

In fiscal 2017, the Company granted to management and other key employees 237,358 restricted stock units that vest ratably over four years from the date of grant at a fair value of $57.60 per restricted stock unit and 83,720 TSRs at a weighted average fair value of $70.79 per unit at the date of grant that cliff vest three years from the date of grant.

For purposes of determining the fair value of the PSUs granted in fiscal 2019, the Company used the market price at the date of grant to which a discount for illiquidity was applied to reflect post vesting restrictions.

For purposes of determining the fair value of TSRs granted in fiscal 2019, fiscal 2018, and fiscal 2017, the Company used a Monte Carlo Simulation with the following assumptions:



	2019		2018		2017
Risk-free interest rate	2.66	%	1.57	%	0.94	%
Dividend yield	—	%	—	%	—	%
Expected life (years)	3		3		3
Volatility	26.41	%	27.49	%	31.74	%

A summary of the changes in restricted stock units, TSRs and PSUs awarded to employees and directors that were outstanding under the Company’s equity compensation plans during fiscal 2019 is presented below:



	Restricted Stock Units (RSU)				Market condition-based Share Units (TSR)				Performance condition-based Share Units (PSU)
	Number of RSU		Weighted- Average Grant Date Fair Value		Number of TSR		Weighted- Average Grant Date Fair Value		Number of PSU		Weighted- Average Grant Date
Non-vested awards as of March 31, 2018	633,751		$	56.60	349,941		$	70.22	—		$	—
Granted	241,105		69.43		36,646		85.84		45,883		68.48
Stock dividend	6,087		56.81		3,131		72.60		320		68.48
Performance factor	—		—		143		75.48		—		—
Vested	(148,487	)	68.55		(3,482	)	59.94		—		—
Canceled	(10,809	)	72.56		(33,795	)	62.21		(3,677	)	68.48
Non-vested awards as of March 31, 2019	721,647		$	57.72	352,584		$	72.83	42,526		$	68.48

The Company recognized stock-based compensation expense relating to restricted stock units, TSRs and PSUs of $19,357, with a related tax benefit of $3,085 for fiscal 2019, $16,712, with a related tax benefit of $3,325 for fiscal 2018 and $17,480, with a related tax benefit of $4,210 for fiscal 2017.

All Award Plans

As of March 31, 2019, unrecognized compensation expense associated with the non-vested equity awards outstanding was $37,187 and is expected to be recognized over a weighted-average period of 20 months.

Earnings Per Share

12 Months Ended

Mar. 31, 2018

Restructuring and Related Activities [Abstract]

The following table sets forth the reconciliation from basic to diluted weighted-average number of common shares outstanding and the calculations of net earnings per common share attributable to EnerSys stockholders.



	Fiscal year ended March 31,
	2019		2018		2017
Net earnings attributable to EnerSys stockholders	$	160,239	$	119,594	$	160,214
Weighted-average number of common shares outstanding:
Basic	42,335,023		42,612,036		43,389,333
Dilutive effect of:
Common shares from exercise and lapse of equity awards, net of shares assumed reacquired	673,929		507,820		623,210
Diluted weighted-average number of common shares outstanding	43,008,952		43,119,856		44,012,543
Basic earnings per common share attributable to EnerSys stockholders	$	3.79	$	2.81	$	3.69
Diluted earnings per common share attributable to EnerSys stockholders	$	3.73	$	2.77	$	3.64
Anti-dilutive equity awards not included in diluted weighted-average common shares	355,728		59,482		1,295

Commitments, Contingencies and Litigation	12 Months Ended
Commitments, Contingencies and Litigation	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Litigation	Commitments, Contingencies and Litigation Litigation and Other Legal Matters In the ordinary course of business, the Company and its subsidiaries are routinely defendants in or parties to pending and threatened legal actions and proceedings, including actions brought on behalf of various classes of claimants. These actions and proceedings are generally based on alleged violations of environmental, anticompetition, employment, contract and other laws. In some of these actions and proceedings, claims for substantial monetary damages are asserted against the Company and its subsidiaries. In the ordinary course of business, the Company and its subsidiaries are also subject to regulatory and governmental examinations, information gathering requests, inquiries, investigations, and threatened legal actions and proceedings. In connection with formal and informal inquiries by federal, state, local and foreign agencies, the Company and its subsidiaries receive numerous requests, subpoenas and orders for documents, testimony and information in connection with various aspects of their activities. European Competition Investigations Certain of the Company’s European subsidiaries had received subpoenas and requests for documents and, in some cases, interviews from, and have had on-site inspections conducted by the competition authorities of Belgium, Germany and the Netherlands relating to conduct and anticompetitive practices of certain industrial battery participants. The Company settled the Belgian regulatory proceeding in February 2016 by acknowledging certain anticompetitive practices and conduct and agreeing to pay a fine of $1,962, which was paid in March 2016. During fiscal 2019, the Company paid $2,402 towards certain aspects of this matter, which are under appeal. As of March 31, 2019 and March 31, 2018, the Company had a reserve balance of $0 and $2,326, respectively. In June 2017, the Company settled a portion of its previously disclosed proceeding involving the German competition authority relating to conduct involving the Company's motive power battery business and agreed to pay a fine of $14,811, which was paid in July 2017. Also in June 2017, the German competition authority issued a fining decision related to the Company's reserve power battery business, which constitutes the remaining portion of the previously disclosed German proceeding. The Company had appealed this decision. In March 2019, the Company settled this matter by agreeing to pay $7,258, which was paid in April 2019. As of March 31, 2019 and March 31, 2018, the Company had a reserve balance of $7,258 and $0, respectively. In July 2017, the Company settled the Dutch regulatory proceeding and agreed to pay a fine of $11,229, which was paid in August 2017. As of March 31, 2019 and March 31, 2018, the Company had a total reserve balance of $7,258 and $2,326, respectively, in connection with these investigations and other related legal matters, included in accrued expenses on the Consolidated Balance Sheets. The foregoing estimate of losses is based upon currently available information for these proceedings. However, the precise scope, timing and time period at issue, as well as the final outcome of the investigations or customer claims, remain uncertain. Accordingly, the Company’s estimate may change from time to time, and actual losses could vary. EnerSys Sarl Litigation One of the parties to a litigation related to a 1999 fire in a French hotel under construction involving the Company’s French subsidiary, EnerSys Sarl, which was acquired by the Company in 2002, that was adverse to the Company, appealed the ruling by the Court of Appeal of Lyon on June 11, 2013, which ruled in the Company’s favor, entitling the Company to a refund of the monies paid of €2,000, or $2,756 to the French Supreme Court, which appeal was denied in January 2015. During the third quarter of fiscal 2019, the Company and the adverse party settled this final item with the Company receiving a refund, including interest, from the adverse party of €2,500, or $2,843, for monies paid. The Company believes that it has no further liability with respect to this matter. Environmental Issues As a result of its operations, the Company is subject to various federal, state and local, as well as international environmental laws and regulations and is exposed to the costs and risks of registering, handling, processing, storing, transporting, and disposing of hazardous substances, especially lead and acid. The Company’s operations are also subject to federal, state, local and international occupational safety and health regulations, including laws and regulations relating to exposure to lead in the workplace. The Company is responsible for certain cleanup obligations at the former Yuasa battery facility in Sumter, South Carolina that predates its ownership of this facility. This manufacturing facility was closed in 2001 and the Company established a reserve for this facility which was $1,081 and $1,109 as of March 31, 2019 and 2018, respectively. Based on current information, the Company’s management believes this reserve is adequate to satisfy the Company’s environmental liabilities at this facility. This facility is separate from the Company’s current metal fabrication facility in Sumter. Collective Bargaining At March 31, 2019, the Company had approximately 11,000 employees. Of these employees, approximately 27% were covered by collective bargaining agreements. Employees covered by collective bargaining agreements that expire in the next twelve months were approximately 10% of the total workforce. The average term of these agreements is 2 years, with the longest term being 3 years. The Company considers its employee relations to be good and did not experience any significant labor unrest or disruption of production during fiscal 2019. Lead and Foreign Currency Forward Contracts To stabilize its lead costs and reduce volatility from currency movements, the Company enters into contracts with financial institutions. The vast majority of such contracts are for a period not extending beyond one year. Please refer to Note 12 - Derivative Financial Instruments for more details. Other The Company has various purchase and capital commitments incidental to the ordinary conduct of business. In the aggregate, such commitments are not at prices in excess of current market.

Restructuring Plans and Other Exit Charges

12 Months Ended

Mar. 31, 2019

Restructuring Plans and Other Exit Charges

Restructuring and Other Exit Charges

Restructuring Plans

During fiscal 2016, the Company announced restructurings to improve efficiencies primarily related to its motive power assembly and distribution center in Italy and its sales and administration organizations in EMEA. In addition, the Company announced a further restructuring related to its manufacturing operations in Europe. The program was completed during the third quarter of fiscal 2018. Total charges for this program were $6,568, primarily for cash expenses of $6,161 for employee severance payments of 130 employees and other charges of $407. In fiscal 2016, 2017 and 2018, the Company recorded restructuring charges of $5,232, $1,251 and $85, respectively. In fiscal 2016, 2017 and 2018 the Company incurred costs against the accrual of $2,993, $3,037 and $499, respectively.

During fiscal 2016, the Company announced a restructuring related to improving the efficiency of its manufacturing operations in the Americas. The program, which was completed during the first quarter of fiscal 2017, consisted of closing its Cleveland, Ohio charger manufacturing facility and the transfer of charger production to other Americas manufacturing facilities. The total charges for all actions associated with this program amounted to $2,379, primarily from cash charges for employee severance-related payments and other charges of $1,043, along with a pension curtailment charge of $313 and non-cash charges related to the accelerated depreciation of fixed assets of $1,023. The program resulted in the reduction of 100 employees at its Cleveland facility. In fiscal 2016, the Company recorded restructuring charges of $1,488 including a pension curtailment charge of $313 and non-cash charges of $305 and recorded an additional $174 in cash charges and $718 in non-cash charges during the first quarter of fiscal 2017. The Company incurred $119 in costs against the accrual in fiscal 2016 and incurred an additional $924 against the accrual during the first quarter of fiscal 2017.

During fiscal 2017, the Company announced restructuring programs to improve efficiencies primarily related to its motive power production in EMEA. This program was completed during fiscal 2019. The total charges for these actions were $4,714, primarily from cash charges for employee severance-related payments and other charges. These actions resulted in the reduction of 45 employees. During fiscal 2017, the Company recorded restructuring charges of $3,104 and an additional $1,610 during fiscal 2018. The Company incurred $749 in costs against the accrual in fiscal 2017 and an additional $2,403 during fiscal 2018. During fiscal 2019, the Company incurred $1,682 against the accrual.

During fiscal 2017, the Company announced restructurings primarily to complete the transfer of equipment and clean-up of its manufacturing facility located in Jiangdu, the People’s Republic of China, which stopped production during the first quarter of fiscal 2016. This program was completed during the fourth quarter of fiscal 2018. The total cash charges for these actions amounted to $991. During fiscal 2017, the Company recorded restructuring charges of $779 and an additional $212 during fiscal 2018. The Company incurred $648 in costs against the accrual in fiscal 2017 and an additional $341 during fiscal 2018.

During fiscal 2018, the Company announced restructuring programs to improve efficiencies primarily related to supply chain, manufacturing and general operations in EMEA. The Company estimates that the total charges for these actions will amount to approximately $7,700, primarily from cash charges for employee severance-related payments and other charges. The Company estimates that these actions will result in the reduction of approximately 85 employees upon completion. During fiscal 2018, the Company recorded non-cash restructuring charges of $69 and cash charges of $2,260 and incurred $1,350 in costs against the accrual. During fiscal 2019, the Company recorded restructuring charges of $3,104 and incurred $2,844 in costs against the accrual. As of March 31, 2019, the reserve balance associated with these actions is $1,061. The Company expects to be committed to an additional $2,200 in restructuring charges related to this action, which it expects to complete in fiscal 2020.

During the second quarter of fiscal 2018, the Company completed the sale of its Cleveland, Ohio facility and recorded a non-cash loss on the sale of the building of $210 and other cash charges of $75. The Cleveland facility ceased charger production in fiscal 2017.

During fiscal 2018, the Company announced a restructuring program to improve efficiencies of its general operations in the Americas. This program was completed during fiscal 2019. The total charges for these actions were $960, from cash charges for employee severance-related payments to approximately 60 salaried employees. During fiscal 2018, the Company recorded restructuring charges of $960 and incurred $755 in costs against the accrual. During fiscal 2019, the Company incurred $207 in costs against the accrual.

During fiscal 2019, the Company announced restructuring programs to improve efficiencies of its operations in EMEA. The Company estimates that the total charges for these actions will amount to approximately $2,500, from charges primarily for employee severance-related payments to approximately 35 employees. During fiscal 2019, the Company recorded restructuring

charges of $347 and incurred $83 in costs against the accrual. As of March 31, 2019, the reserve balance associated with these actions is $262. The Company expects to complete this action in fiscal 2020.

During fiscal 2019, the Company announced restructuring programs to improve efficiencies of its operations in the Americas. The Company estimates that the total charges for these actions will amount to approximately $4,600, from cash charges primarily for employee severance-related payments to approximately 100 employees and non-cash stock compensation charges. During fiscal 2019, the Company recorded cash restructuring charges of $1,970, non-cash charges of $2,095 and incurred $1,480 in costs against the accrual. As of March 31, 2019, the reserve balance associated with these actions is $490. The Company expects to complete these action in fiscal 2020.

During fiscal 2019, the Company announced restructuring programs to improve efficiencies of its operations in Asia and to convert its India operations from mainly reserve power production to motive power production. The Company estimates that the total charges for these actions will amount to approximately $4,500, from cash charges for employee severance-related payments to approximately 150 employees, other charges and non-cash charges related to stock compensation and the write-off of fixed assets. During fiscal 2019, the Company recorded cash restructuring charges of $2,772 and non-cash charges of $771 and incurred $1,683 in costs against the accrual. As of March 31, 2019, the reserve balance associated with these actions is $1,139. The Company expects to complete these actions in fiscal 2020.

A roll-forward of the restructuring reserve is as follows:



	Employee Severance			Other			Total
Balance at March 31, 2016	$	2,964		$	25		$	2,989
Accrued	4,566			742			5,308
Costs incurred	(4,754		)	(604		)	(5,358		)
Foreign currency impact and other	(108		)	(19		)	(127		)
Balance at March 31, 2017	$	2,668		$	144		$	2,812
Accrued	4,757			445			5,202
Costs incurred	(4,849		)	(574		)	(5,423		)
Foreign currency impact and other	317			1			318
Balance at March 31, 2018	$	2,893		$	16		$	2,909
Accrued	6,554			1,639			8,193
Costs incurred	(6,893		)	(1,086		)	(7,979		)
Foreign currency impact and other	(198		)	27			(171		)
Balance at March 31, 2019	$	2,356		$	596		$	2,952

Other Exit Charges

During fiscal 2019, the Company committed to a plan to close its facility in Targovishte, Bulgaria, which produced diesel-electric submarine batteries. Management determined that the future demand for batteries of diesel-electric submarines was not sufficient given the number of competitors in the market. The Company estimates that the total charges for these actions will amount to approximately $30,000. The Company recorded charges of $17,652 included under restructuring and exit charges, comprising of $2,694 relating to severance and $14,958 of fixed asset write-offs. The Company also wrote off inventories of $2,590, which was reported in cost of goods sold. The Company expects to complete this action in fiscal 2020.

During fiscal 2019, the Company recorded exit charges of $4,930 relating to the disposition of GAZ Geräte- und Akkumulatorenwerk Zwickau GmbH, a wholly-owned German subsidiary and $957 relating to dissolving a joint venture in Tunisia. These exit activities are a consequence of the Company's strategic decision to streamline its product portfolio and focus its efforts on new technologies.

During fiscal 2019, in an effort to improve profitability in Asia, the Company converted its India operations from mainly reserve power production to motive power production. As a result of the Company’s exit from reserve power, the Company recorded a non-cash write off of reserve power inventories of $526, which was reported in cost of goods sold and a $660 non-cash write-off related to reserve power fixed assets in restructuring charges.

During fiscal 2018, the Company wrote off $3,457 of inventories, relating to the closing of its Cleveland, Ohio charger manufacturing facility, which was reported in cost of goods sold.

During fiscal 2018, the Company recorded exit charges of $3,292 related to the South Africa joint venture, consisting of cash charges of $2,575 primarily relating to severance and non-cash charges of $717. Included in the non-cash charges were $2,157 relating to the inventory adjustment which was reported in cost of goods sold, partially offset by a credit of $1,099 relating to a change in estimate of contract losses and a $341 gain on deconsolidation of the joint venture. Weakening of the general economic environment in South Africa, reflecting the limited growth in the mining industry, affected the joint venture’s ability to compete effectively in the marketplace and consequently, the Company initiated an exit plan in consultation with its joint venture partner in the second quarter of fiscal 2018. The joint venture was under liquidation, which resulted in a loss of control and deconsolidation of the joint venture. The impact of the deconsolidation has been reflected in the Consolidated Statement of Income in fiscal 2018 and was deemed not material.

Warranty

12 Months Ended

Mar. 31, 2019

Warranty

The Company provides for estimated product warranty expenses when the related products are sold, with related liabilities included within accrued expenses and other liabilities. As warranty estimates are forecasts that are based on the best available information, primarily historical claims experience, claims costs may ultimately differ from amounts provided. An analysis of changes in the liability for product warranties is as follows:



	Fiscal year ended March 31,
	2019			2018			2017
Balance at beginning of year	$	50,602		$	46,116		$	48,422
Current year provisions	23,679			21,706			17,852
Costs incurred	(25,053		)	(18,820		)	(15,945		)
Warranty reserves of acquired business - Alpha	7,535			—			—
Foreign currency translation adjustment	(2,195		)	1,600			(4,213		)
Balance at end of year	$	54,568		$	50,602		$	46,116

Other (Income) Expense, Net

12 Months Ended

Mar. 31, 2019

Other (Income) Expense, Net

Other (income) expense, net consists of the following:



	Fiscal year ended March 31,
	2019			2018		2017
Foreign exchange transaction (gains) losses	$	(3,044	)	$	5,499	$	(662	)
Non-service components of pension expense	1,502			1,464		1,252
Other	928			556		1,631
Total	$	(614	)	$	7,519	$	2,221

Business Segments

12 Months Ended

Mar. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

Business Segments

Summarized financial information related to the Company’s reportable segments at March 31, 2019, 2018 and 2017 and for each of the fiscal years then ended is shown below.



	Fiscal year ended March 31,
	2019			2018			2017
Net sales by segment to unaffiliated customers
Americas	$	1,690,912		$	1,429,888		$	1,332,353
EMEA	860,563			849,420			763,013
Asia	256,542			302,583			271,783
Total net sales	$	2,808,017		$	2,581,891		$	2,367,149
Net sales by product line
Reserve power	$	1,416,173		$	1,247,900		$	1,142,327
Motive power	1,391,844			1,333,991			1,224,822
Total net sales	$	2,808,017		$	2,581,891		$	2,367,149
Intersegment sales
Americas	$	28,753		$	29,513		$	26,039
EMEA	123,274			133,164			93,150
Asia	34,531			23,375			22,584
Total intersegment sales⁽¹⁾	$	186,558		$	186,052		$	141,773
Operating earnings by segment
Americas	$	186,814		$	189,466		$	191,801
EMEA	71,963			77,671			77,376
Asia	3,213			12,647			14,994
Inventory step up to fair value relating to acquisition - Americas	(7,263		)	—			—
Inventory adjustment relating to exit activities - Americas	—			(3,457		)	—
Inventory adjustment relating to exit activities - EMEA	(2,590		)	—			(2,157		)
Inventory adjustment relating to exit activities - Asia	(526		)	—			—
Restructuring charges - Americas	(4,066		)	(1,246		)	(892		)
Restructuring and other exit charges - EMEA	(26,989		)	(4,023		)	(5,487		)
Restructuring charges - Asia	(3,654		)	(212		)	(781		)
Impairment of goodwill and indefinite-lived intangibles - Americas	—			—			(9,346		)
Impairment of goodwill and indefinite-lived intangibles - EMEA	—			—			(4,670		)
Legal proceedings charge, net - EMEA	(4,437		)	—			(23,725		)
Total operating earnings⁽²⁾	$	212,465		$	270,846		$	237,113
Property, plant and equipment, net
Americas	$	257,559		$	210,998		$	190,169
EMEA	94,932			118,263			100,042
Asia	56,948			60,999			58,338
Total	$	409,439		$	390,260		$	348,549
Capital Expenditures
Americas	$	45,029		$	46,905		$	34,809
EMEA	18,972			18,392			13,733
Asia	6,371			4,535			1,530
Total	$	70,372		$	69,832		$	50,072
Depreciation and Amortization
Americas	$	40,675		$	30,421		$	30,204
EMEA	15,128			16,198			15,693
Asia	7,545			7,698			8,048
Total	$	63,348		$	54,317		$	53,945


(1)	Intersegment sales are presented on a cost-plus basis which takes into consideration the effect of transfer prices between legal entities.


(2)	The Company does not allocate interest expense or other (income) expense, net, to the reportable segments.

The Company markets its products and services in over 100 countries. Sales are attributed to countries based on the location of sales order approval and acceptance. Sales to customers in the United States were 48.5%, 49.2% and 50.0% for fiscal years ended March 31, 2019, 2018 and 2017, respectively. Property, plant and equipment, net, attributable to the United States as of March 31, 2019 and 2018, were $202,985 and $176,144, respectively. No single country, outside the United States, accounted for more than 10% of the consolidated net sales or net property, plant and equipment and, therefore, was deemed not material for separate disclosure.

Quarterly Financial Data (Unaudited)

12 Months Ended

Mar. 31, 2018

Quarterly Financial Data (Unaudited)

The Company reports interim financial information for 13-week periods, except for the first quarter, which always begins on April 1, and the fourth quarter, which always ends on March 31. The four quarters in fiscal 2019 ended on July 1, 2018, September 30, 2018, December 30, 2018, and March 31, 2019, respectively. The four quarters in fiscal 2018 ended on July 2, 2017, October 1, 2017, December 31, 2017, and March 31, 2018, respectively.



	1st Quarter		2nd Quarter		3rd Quarter			4th Quarter		Fiscal Year
Fiscal year ended March 31, 2019
Net sales	$	670,930	$	660,462	$	680,022		$	796,603	$	2,808,017
Gross profit	165,334		160,880		164,546			202,266		693,026
Operating earnings^(1)(3)(5)	64,179		63,357		49,951			34,978		212,465
Net earnings⁽⁶⁾	46,020		47,447		48,614			18,546		160,627
Net earnings attributable to EnerSys stockholders	45,860		47,424		48,417			18,538		160,239
Net earnings per common share attributable to EnerSys stockholders—basic	$	1.09	$	1.13	$	1.14		$	0.43	$	3.79
Net earnings per common share attributable to EnerSys stockholders—diluted	$	1.08	$	1.11	$	1.12		$	0.42	$	3.73
Fiscal year ended March 31, 2018
Net sales	$	622,625	$	617,289	$	658,935		$	683,042	$	2,581,891
Gross profit	163,458		160,248		167,310			167,388		658,404
Operating earnings⁽²⁾⁽⁴⁾	69,972		64,364		68,785			67,725		270,846
Net earnings (loss)⁽⁷⁾	48,322		43,151		(25,779		)	54,139		119,833
Net earnings (loss) attributable to EnerSys stockholders	48,201		43,222		(25,847		)	54,018		119,594
Net earnings (loss) per common share attributable to EnerSys stockholders—basic	$	1.11	$	1.01	$	(0.61	)	$	1.29	$	2.81
Net earnings (loss) per common share attributable to EnerSys stockholders—diluted	$	1.09	$	1.00	$	(0.61	)	$	1.27	$	2.77


(1)	Included in Operating earnings were inventory adjustment relating to exit activities of $526 and $2,590 in the first and fourth quarter of fiscal 2019, respectively. Also included were inventory adjustments relating to Alpha acquisition of $3,747 and $3,516 in the third and fourth quarter of fiscal 2019, respectively.


(2)	Included in Operating earnings were inventory adjustment relating to exit activities of $3,457 in the fourth quarter of fiscal 2018, respectively.


(3)	Included in Operating earnings were restructuring and other exit charges of $1,739, $1,121, $5,392 and $26,457 for the first, second, third and fourth quarters of fiscal 2019, respectively.


(4)	Included in Operating earnings were restructuring and other exit charges of $833, $1,776, $1,808 and $1,064 for the first, second, third and fourth quarters of fiscal 2018, respectively.


(5)	Included in Operating earnings were legal proceedings settlement income of $2,843 in the third quarter and expense of $7,280 in the fourth quarter of fiscal 2019.


(6)	Included in net earnings was a tax benefit of $13,483 for the third quarter of fiscal 2019, on account of the Tax Act.

(7)

Included in net earnings (loss) was tax expense of $77,347 and $4,106 for the third and fourth quarters of fiscal 2018, respectively, on account of the Tax Act.

Subsequent Events	12 Months Ended
Subsequent Events	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On May 16, 2019, the Company announced the payment of a quarterly cash dividend of $0.175 per share of common stock to be paid on June 28, 2019, to stockholders of record as of June 14, 2019.

Valuation and Qualifying Accounts

12 Months Ended

Mar. 31, 2019

SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]

Valuation and Qualifying Accounts



	Balance at Beginning of Period		Additions Charged to Expense		Write-Offs Net of Recoveries			Other⁽¹⁾			Balance at End of Period
Allowance for doubtful accounts:
Fiscal year ended March 31, 2017	$	11,393	$	1,794	$	(173	)	$	(352	)	$	12,662
Fiscal year ended March 31, 2018	12,662		822		(1,400		)	559			12,643
Fiscal year ended March 31, 2019	12,643		1,385		(2,459		)	(756		)	10,813

Tax Valuation Allowance



	Balance at Beginning of Period		Additions Charged to Expense		Valuation Allowance Reversal			Business Combination Adjustments		Other^{(1) (2) (3)}			Balance at End of Period
Deferred tax asset—valuation allowance:
Fiscal year ended March 31, 2017	$	25,416	$	4,305	$	(2,255	)	$	—	$	(413	)	$	27,053
Fiscal year ended March 31, 2018	27,053		4,853		(14,132		)	—		(2,519		)	15,255
Fiscal year ended March 31, 2019	15,255		2,978		(99		)	1,157		(1,772		)	17,519


(1)	Primarily the impact of currency changes.


(2)	In fiscal 2019, “Other” included expiration of net operating losses for which a full valuation allowance was recorded.

(3)

In fiscal 2018, “Other” also included an offset to adjustments to foreign net operating losses for which a full valuation allowance was recorded.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Mar. 31, 2019

Principles of Consolidation

Description of Business

Foreign Currency Translation

Revenue Recognition

ASC 606, Revenue from Contracts with Customers, was adopted for the fiscal year beginning April 1, 2018.

Concurrent with the adoption of the new standard, the Company has updated its revenue recognition policy as follows:

The Company determines revenue recognition by applying the following steps:

1. identify the contract with a customer;

2. identify the performance obligations in the contract;

3. determine the transaction price;

4. allocate the transaction price to the performance obligations; and

5. recognize revenue as the performance obligations are satisfied.

The Company's primary performance obligation to its customers is the delivery of finished goods and products, pursuant to

purchase orders. Control of the products sold typically transfers to its customers at the point in time when the goods are shipped

as this is also when title generally passes to its customers under the terms and conditions of our customer arrangements.

The Company's typical payment terms are 30 days and sales arrangements do not contain any significant financing component for its customers.

The Company applies a policy election to exclude transaction taxes collected from customers from sales when the tax is both imposed on and concurrent with a specific revenue-producing transaction.

Warranties

Cash and Cash Equivalents

Cash and cash equivalents include all highly liquid investments with an original maturity of three months or less when purchased.

Concentration of Credit Risk

Accounts Receivable

Inventories are stated at the lower of cost or market. Cost is determined using the first-in, first-out (FIFO) method. The cost of inventory consists of material, labor, and associated overhead.

Maintenance and repairs are expensed as incurred. Interest on capital projects is capitalized during the construction period.

Business Combinations

intangible assets is recorded to goodwill. The results of operations of the acquired business are included in the Company’s operating results from the date of acquisition.

Impairment of Long-Lived Assets

Environmental Expenditures

The Company does not have any credit-related contingent features associated with its derivative instruments.

The Company groups its recurring, non-recurring and disclosure-only fair value measurements into the following levels when making fair value measurement disclosures:



Level 1		Inputs are unadjusted quoted prices in active markets for identical assets or liabilities.

Level 2		Inputs are quoted prices for similar assets or liabilities in an active market, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable and market-corroborated inputs which are derived principally from or corroborated by observable market data.

Level 3		Inputs are derived from valuation techniques in which one or more significant inputs or value drivers are unobservable.

Stock-Based Compensation Plans

The Company recognizes tax related interest and penalties in income tax expense in its Consolidated Statement of Income.

Deferred Financing Fees

Market and Performance condition-based awards

The Company grants market condition-based awards and performance condition-based awards.

Restricted Stock Units

Stock Options

New Accounting Pronouncements

Segment Reporting


•	Americas, which includes North and South America, with segment headquarters in Reading, Pennsylvania, U.S.A.,


•	EMEA, which includes Europe, the Middle East and Africa, with segment headquarters in Zug, Switzerland, and

•

Asia, which includes Asia, Australia and Oceania, with segment headquarters in Singapore.

Accounting Pronouncements

Accounting Pronouncements Issued But Not Adopted as of March 31, 2019


•	to adopt the optional transition method defined within ASU 2018-11 and not restate comparative prior periods but instead recognize a cumulative effect adjustment to the opening balance of retained earnings in the period of adoption;


•	to elect the package of three practical expedients addressing whether a contract contains a lease, lease classification and initial direct costs;

to combine lease and non-lease components as a single component for all asset classes;


•	to use a portfolio approach to determine the incremental borrowing rate; and


•	to apply the short-term lease exception to leases that, at the commencement date, has a lease term of 12 months or less and does not include an option to purchase the underlying asset that the lessee is reasonably certain to exercise.

Use of Estimates

Acquisition (Tables)

12 Months Ended

Mar. 31, 2019

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed

The acquired assets and assumed liabilities include the following:



Accounts receivable	$	115,467
Inventories	84,297
Other current assets	6,822
Other intangible assets	332,000
Property, plant and equipment	20,987
Other assets	9,005
Total assets acquired	$	568,578
Accounts payable	35,803
Accrued liabilities	41,918
Deferred income taxes	56,331
Other liabilities	12,642
Total liabilities assumed	$	146,694
Net assets acquired	$	421,884

Purchase price:
Cash paid for net assets acquired	$	650,000
Fair value of shares issued for net assets acquired	93,268
Working capital adjustment	(766		)
Total purchase consideration	742,502
Less: Fair value of acquired identifiable assets and liabilities	421,884
Goodwill	$	320,618

Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination

The following table summarizes the estimated fair value of Alpha's identifiable intangible assets and the initial assessment of their respective estimated lives:



	Type	Life in Years	Fair Value
Trademarks	Indefinite-lived	Indefinite	$	56,000
Customer relationships	Finite-lived	14	221,000
Technology	Finite-lived	10	55,000
Total identifiable intangible assets			$	332,000

Business Acquisition, Pro Forma Information

The following unaudited summary information is presented on a consolidated pro forma basis as if the acquisition had occurred on April 1, 2017:



	Fiscal year ended
	March 31, 2019		March 31, 2018
Net sales	$	3,278,646	$	3,124,527
Net earnings attributable to EnerSys stockholders	207,904		126,965
Net earnings per share attributable to EnerSys stockholders - basic	4.79		2.90
Net earnings per share attributable to EnerSys stockholders - assuming dilution	4.71		2.87

Inventories (Tables)

12 Months Ended

Mar. 31, 2019

Summary Of Net Inventories



	March 31,
	2019		2018
Raw materials	$	138,718	$	92,216
Work-in-process	129,736		136,068
Finished goods	235,415		185,950
Total	$	503,869	$	414,234

Property, Plant, and Equipment (Tables)

12 Months Ended

Mar. 31, 2019

Summary Of Property, Plant, And Equipment

Property, plant, and equipment consist of:



	March 31,
	2019			2018
Land, buildings, and improvements	$	268,006		$	273,506
Machinery and equipment	683,955			657,262
Construction in progress	54,278			49,900
	1,006,239			980,668
Less accumulated depreciation	(596,800		)	(590,408		)
Total	$	409,439		$	390,260

Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Mar. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule Of Company's Other Intangible Assets

Information regarding the Company’s other intangible assets are as follows:



	March 31,
	2019							2018
	Gross Amount		Accumulated Amortization			Net Amount		Gross Amount		Accumulated Amortization			Net Amount
Indefinite-lived intangible assets:
Trademarks	$	152,484	$	(953	)	$	151,531	$	97,444	$	(953	)	$	96,491
Finite-lived intangible assets:
Customer relationships	286,664		(42,704		)	243,960		66,973		(31,500		)	35,473
Non-compete	3,025		(2,807		)	218		2,852		(2,759		)	93
Technology	77,779		(12,229		)	65,550		22,769		(8,872		)	13,897
Trademarks	2,003		(1,236		)	767		2,003		(1,151		)	852
Licenses	1,477		(1,187		)	290		1,491		(1,156		)	335
Total	$	523,432	$	(61,116	)	$	462,316	$	193,532	$	(46,391	)	$	147,141

Schedule Of Changes In The Carrying Amount Of Goodwill By Business Segment

The changes in the carrying amount of goodwill by reportable segment are as follows:



	Fiscal year ended March 31, 2019
	Americas			EMEA			Asia			Total
Balance at beginning of year	$	151,255		$	155,825		$	45,725		$	352,805
Acquisitions during the year	320,618			—			—			320,618
Foreign currency translation adjustment	(1,679		)	(12,556		)	(2,789		)	(17,024		)
Balance at end of year	$	470,194		$	143,269		$	42,936		$	656,399



	Fiscal year ended March 31, 2018
	Americas		EMEA		Asia		Total
Balance at beginning of year	$	146,982	$	138,813	$	42,862	$	328,657
Acquisitions during the year	3,670		—		—		3,670
Foreign currency translation adjustment	603		17,012		2,863		20,478
Balance at end of year	$	151,255	$	155,825	$	45,725	$	352,805

A reconciliation of goodwill and accumulated goodwill impairment losses, by reportable segment, is as follows:



	March 31, 2019
	Americas			EMEA			Asia			Total
Gross carrying value	$	528,039		$	149,422		$	48,115		$	725,576
Accumulated goodwill impairment charges	(57,845		)	(6,153		)	(5,179		)	(69,177		)
Net book value	$	470,194		$	143,269		$	42,936		$	656,399



	March 31, 2018
	Americas			EMEA			Asia			Total
Gross carrying value	$	209,100		$	161,978		$	50,904		$	421,982
Accumulated goodwill impairment charges	(57,845		)	(6,153		)	(5,179		)	(69,177		)
Net book value	$	151,255		$	155,825		$	45,725		$	352,805

Prepaid and Other Current Assets (Tables)

12 Months Ended

Mar. 31, 2019

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Schedule Of Prepaid And Other Current Assets

Prepaid and other current assets consist of the following:



	March 31,
	2019		2018
Contract assets	$	38,778	$	—
Prepaid non-income taxes	22,490		22,583
Non-trade receivables	10,823		4,087
Prepaid income taxes	9,608		8,921
Other	27,732		21,319
Total	$	109,431	$	56,910

Accrued Expenses (Tables)

12 Months Ended

Mar. 31, 2019

Summary Of Accrued Expenses

Accrued expenses consist of the following:



	March 31,
	2019		2018
Payroll and benefits	$	54,285	$	50,053
Accrued selling expenses	35,394		34,831
Warranty	21,646		22,637
VAT and other non-income taxes	17,125		13,155
Project related accruals	16,301		—
Contract liabilities	15,162		—
Freight	14,423		15,810
Income taxes payable	9,234		19,696
Legal proceedings	7,258		2,326
Interest	7,248		6,762
Tax Act - Transition Tax	5,290		7,800
Restructuring	2,952		2,909
Pension	1,207		1,657
Deferred income	—		9,387
Other	48,356		27,095
Total	$	255,881	$	214,118

Debt (Tables)

12 Months Ended

Mar. 31, 2019

Schedule Of Long-Term Debt

The following summarizes the Company’s long-term debt:



	As of March 31,
	2019				2018
	Principal		Unamortized Issuance Costs		Principal		Unamortized Issuance Costs
5.00% Senior Notes, due 2023	$	300,000	$	2,497	$	300,000	$	3,122
Amended Credit Facility, due 2022^*	677,315		3,062		285,500		2,843
	$	977,315	$	5,559	$	585,500	$	5,965
Less: Unamortized issuance costs	5,559				5,965
Less: Current portion	—				—
Long-term debt, net of unamortized issuance costs	$	971,756			$	579,535

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

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Leases (Tables)

12 Months Ended

Mar. 31, 2019

Schedule Of Capital And Operating Leases

The Company’s future minimum lease payments under operating leases that have noncancelable terms in excess of one year as of March 31, 2019 are as follows:




2020	$	31,483
2021	24,290
2022	16,514
2023	11,596
2024	8,683
Thereafter	23,757
Total minimum lease payments	$	116,323

Other Liabilities (Tables)

12 Months Ended

Mar. 31, 2019

Schedule Of Other Long-Term Liabilities

Other liabilities consist of the following:



	March 31,
	2019		2018
Tax Act - Transition Tax	$	55,489	$	89,700
Pension	39,924		44,404
Warranty	32,922		27,965
Liability for uncertain tax positions	20,240		1,684
Deferred income	—		7,094
Contract liabilities	6,360		—
Other	10,265		10,240
Total	$	165,200	$	181,087

Fair Value of Financial Instruments (Tables)

12 Months Ended

Mar. 31, 2019

Financial Assets And (Liabilities), Measured At Fair Value On A Recurring Basis

The following tables represent the financial assets and (liabilities) measured at fair value on a recurring basis as of March 31, 2019 and March 31, 2018 and the basis for that measurement:



	Total Fair Value Measurement March 31, 2019			Quoted Price in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Lead forward contracts	$	(902	)	$	—	$	(902	)	$	—
Foreign currency forward contracts	(249		)	—		(249		)	—
Total derivatives	$	(1,151	)	$	—	$	(1,151	)	$	—



	Total Fair Value Measurement March 31, 2018			Quoted Price in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Lead forward contracts	$	(3,877	)	$	—	$	(3,877	)	$	—
Foreign currency forward contracts	22			—		22			—
Total derivatives	$	(3,855	)	$	—	$	(3,855	)	$	—

Carrying Amounts And Estimated Fair Values Of Company's Financial Instruments

The carrying amounts and estimated fair values of the Company’s derivatives and Notes at March 31, 2019 and 2018 were as follows:



	March 31, 2019				March 31, 2018
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Financial assets:
Derivatives⁽¹⁾	$	—	$	—	$	22	$	22
Financial liabilities:
Notes ⁽²⁾	300,000		297,000		300,000		304,500
Derivatives⁽¹⁾	$	1,151	$	1,151	$	3,877	$	3,877


(1)	Represents lead and foreign currency forward contracts (see Note 12 for asset and liability positions of the lead and foreign currency forward contracts at March 31, 2019 and March 31, 2018).


(2)	The fair value amount of the Notes at March 31, 2019 and March 31, 2018 represent the trading value of the instruments.

Derivative Financial Instruments (Tables)

12 Months Ended

Mar. 31, 2019

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Fair Value Of Derivative Instruments In The Consolidated Balance Sheets

Fair Value of Derivative Instruments

March 31, 2019 and 2018



	Derivatives and Hedging Activities Designated as Cash Flow Hedges				Derivatives and Hedging Activities Not Designated as Hedging Instruments
	March 31, 2019		March 31, 2018		March 31, 2019		March 31, 2018
Prepaid and other current assets:
Foreign currency forward contracts	—		209		—		—
Total assets	$	—	$	209	$	—	$	—
Accrued expenses:
Lead forward contracts	$	902	$	3,877	$	—	$	—
Foreign currency forward contracts	8		—		241		187
Total liabilities	$	910	$	3,877	$	241	$	187

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ended March 31, 2017



Derivatives Designated as Cash Flow Hedges	Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)		Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Lead forward contracts	$	7,907	Cost of goods sold	$	5,803
Foreign currency forward contracts	845		Cost of goods sold	433
Total	$	8,752		$	6,236

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ended March 31, 2019



Derivatives Designated as Cash Flow Hedges	Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Lead forward contracts	$	(12,531	)	Cost of goods sold	$	(15,666	)
Foreign currency forward contracts	1,551			Cost of goods sold	385
Total	$	(10,980	)		$	(15,281	)

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ended March 31, 2018



Derivatives Designated as Cash Flow Hedges	Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Lead forward contracts	$	(805	)	Cost of goods sold	$	5,860
Foreign currency forward contracts	(3,524		)	Cost of goods sold	(2,718		)
Total	$	(4,329	)		$	3,142

Effect Of Derivative Instruments



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivatives	Pretax Gain (Loss)
Foreign currency forward contracts	Other (income) expense, net	$	180
Total		$	180



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivatives	Pretax Gain (Loss)
Foreign currency forward contracts	Other (income) expense, net	$	(1,856	)
Total		$	(1,856	)



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivatives	Pretax Gain (Loss)
Foreign currency forward contracts	Other (income) expense, net	$	(471	)
Total		$	(471	)

Tabular disclosure of pertinent information about a derivative or group of derivatives on a disaggregated basis, such as for individual instruments, or small groups of similar instruments. May include a combination of the type of instrument, risks being hedged, notional amount, hedge designation, related hedged item, inception date, maturity date, or other relevant item.

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Income Taxes (Tables)

12 Months Ended

Mar. 31, 2019

Earnings Before Income Taxes

Income Tax Expense



	Fiscal year ended March 31,
	2019			2018			2017
Current income tax expense
Current:
Federal	$	6,377		$	115,315		$	30,362
State	5,027			3,461			4,855
Foreign	16,636			20,030			17,800
Total current income tax expense	28,040			138,806			53,017
Deferred income tax (benefit) expense
Federal	(5,031		)	(9,551		)	857
State	(669		)	789			590
Foreign	(756		)	(11,551		)	8
Total deferred income tax (benefit) expense	(6,456		)	(20,313		)	1,455
Total income tax expense	$	21,584		$	118,493		$	54,472

Earnings before income taxes consists of the following:



	Fiscal year ended March 31,
	2019		2018		2017
United States	$	53,339	$	74,440	$	80,436
Foreign	128,872		163,886		132,259
Earnings before income taxes	$	182,211	$	238,326	$	212,695

Deferred Tax Assets And Liabilities

The following table sets forth the tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities:



	March 31,
	2019			2018
Deferred tax assets:
Accounts receivable	$	1,297		$	1,790
Inventories	4,081			3,660
Net operating loss carryforwards	48,423			50,928
Accrued expenses	21,574			21,274
Capitalized research and development costs	7,061			—
Other assets	17,656			16,832
Gross deferred tax assets	100,092			94,484
Less valuation allowance	(17,519		)	(15,255		)
Total deferred tax assets	82,573			79,229
Deferred tax liabilities:
Property, plant and equipment	25,656			21,045
Intangible assets	96,826			46,058
Other liabilities	1,737			1,331
Total deferred tax liabilities	124,219			68,434
Net deferred tax (liabilities) assets	$	(41,646	)	$	10,795

Reconciliation Of Income Taxes At The Statutory Rate

A reconciliation of income taxes at the statutory rate (21.0% for fiscal 2019, 31.55% for fiscal 2018 and 35% for fiscal 2017) to the income tax provision is as follows:



	Fiscal year ended March 31,
	2019			2018			2017
United States statutory income tax expense	$	38,264		$	75,196		$	74,444
Increase (decrease) resulting from:
Impact of Tax Act	(13,483		)	83,400			—
State income taxes, net of federal effect	3,285			3,146			3,677
Nondeductible expenses, domestic manufacturing deduction (fiscal 2018 and 2017) and other	2,677			1,078			1,993
Legal proceedings charge - European Competition Investigations - See Note 18	2,405			—			7,873
Net effect of GILTI, FDII, BEAT	2,320			—			—
Goodwill impairment - See Note 5	—			—			3,812
Effect of foreign operations	(16,763		)	(35,048		)	(39,377		)
Valuation allowance	2,879			(9,279		)	2,050
Income tax expense	$	21,584		$	118,493		$	54,472

Reconciliation Of Unrecognized Tax Benefits



	Fiscal year ended March 31,
	2019			2018			2017
Balance at beginning of year	$	1,568		$	1,450		$	2,375
Increases related to current year tax positions	129			397			252
Increases related to the Alpha acquisition	7,840			—			—
Increases related to prior year tax positions	11,463			11			31
Decreases related to prior tax positions and foreign currency translation	(544		)	—			(352		)
Decreases related to prior year tax positions settled	(93		)	(1		)	(678		)
Lapse of statute of limitations	(198		)	(289		)	(178		)
Balance at end of year	$	20,165		$	1,568		$	1,450

Retirement Plans (Tables)

12 Months Ended

Mar. 31, 2019

Components Of Net Periodic Pension Cost

Net periodic pension cost for fiscal 2019, 2018 and 2017, includes the following components:



	United States Plans									International Plans
	Fiscal year ended March 31,									Fiscal year ended March 31,
	2019			2018			2017			2019			2018			2017
Service cost	$	—		$	—		$	371		$	997		$	1,025		$	871
Interest cost	631			658			664			1,831			1,795			1,848
Expected return on plan assets	(514		)	(496		)	(816		)	(2,151		)	(2,264		)	(1,875		)
Amortization and deferral	184			303			453			1,520			1,468			978
Net periodic benefit cost	$	301		$	465		$	672		$	2,197		$	2,024		$	1,822

Summary Of Change In Projected Benefit Obligation



	United States Plans						International Plans
	March 31,						March 31,
	2019			2018			2019			2018
Change in projected benefit obligation
Benefit obligation at the beginning of the period	$	16,713		$	16,682		$	82,033		$	74,478
Service cost	—			—			997			1,025
Interest cost	631			658			1,831			1,795
Benefits paid, inclusive of plan expenses	(1,061		)	(1,037		)	(1,758		)	(2,153		)
Plan curtailments and settlements	—			—			(1,130		)	(52		)
Actuarial losses (gains)	364			410			(261		)	(2,705		)
Foreign currency translation adjustment	—			—			(6,674		)	9,645
Benefit obligation at the end of the period	$	16,647		$	16,713		$	75,038		$	82,033

Summary Of Change In Plan Assets



Change in plan assets
Fair value of plan assets at the beginning of the period	$	13,928		$	12,731		$	38,757		$	34,323
Actual return on plan assets	758			1,731			2,109			688
Employer contributions	138			503			1,670			1,865
Benefits paid, inclusive of plan expenses	(1,061		)	(1,037		)	(1,758		)	(2,153		)
Plan curtailments and settlements	—			—			(1,130		)	(52		)
Foreign currency translation adjustment	—			—			(2,857		)	4,086
Fair value of plan assets at the end of the period	$	13,763		$	13,928		$	36,791		$	38,757
Funded status deficit	$	(2,884	)	$	(2,785	)	$	(38,247	)	$	(43,276	)

Summary Of Amounts Recognized In The Balance Sheets



	March 31,
	2019			2018
Amounts recognized in the Consolidated Balance Sheets consist of:
Accrued expenses	(1,207		)	(1,657		)
Other liabilities	(39,924		)	(44,404		)
Total liabilities	$	(41,131	)	$	(46,061	)

Summary Of Amounts In AOCI Before Taxes

The following table represents pension components (before tax) and related changes (before tax) recognized in AOCI for the Company’s pension plans for the years ended March 31, 2019, 2018 and 2017:



	Fiscal year ended March 31,
	2019			2018			2017
Amounts recorded in AOCI before taxes:
Prior service cost	$	(307	)	$	(385	)	$	(377	)
Net loss	(24,051		)	(27,762		)	(28,475		)
Net amount recognized	$	(24,358	)	$	(28,147	)	$	(28,852	)

Summary Of Changes In AOCI



	Fiscal year ended March 31,
	2019			2018			2017
Changes in plan assets and benefit obligations:
New prior service cost	$	—		$	—		$	—
Net loss (gain) arising during the year	(99		)	(1,953		)	5,485
Effect of exchange rates on amounts included in AOCI	(1,984		)	3,019			(2,275		)
Amounts recognized as a component of net periodic benefit costs:
Amortization of prior service cost	(45		)	(46		)	(42		)
Amortization or settlement recognition of net loss	(1,659		)	(1,725		)	(1,389		)
Total recognized in other comprehensive (income) loss	$	(3,787	)	$	(705	)	$	1,779

Summary Of Recognized Components Of Net Periodic Pension Cost Included In Accumulated Other Comprehensive Income

The amounts included in AOCI as of March 31, 2019 that are expected to be recognized as components of net periodic pension cost (before tax) during the next twelve months are as follows:



Prior service cost	$	(44	)
Net loss	(1,185		)
Net amount expected to be recognized	$	(1,229	)

Summary Of Accumulated Benefit Obligation Related To All Defined Pension Plans



	United States Plans				International Plans
	March 31,				March 31,
	2019		2018		2019		2018
All defined benefit plans:
Accumulated benefit obligation	$	16,647	$	16,713	$	71,350	$	77,724
Unfunded defined benefit plans:
Projected benefit obligation	$	—	$	—	$	32,320	$	33,124
Accumulated benefit obligation	—		—		30,328		31,270
Defined benefit plans with a projected benefit obligation in excess of the fair value of plan assets:
Projected benefit obligation	$	16,647	$	16,713	$	75,038	$	82,033
Fair value of plan assets	13,763		13,928		36,791		38,757
Defined benefit plans with an accumulated benefit obligation in excess of the fair value of plan assets:
Projected benefit obligation	$	16,647	$	16,713	$	74,235	$	81,253
Accumulated benefit obligation	16,647		16,713		70,654		77,021
Fair value of plan assets	13,763		13,928		36,077		37,986

Significant Assumptions Used To Determine The Net Periodic Benefit Cost

Significant assumptions used to determine the net periodic benefit cost for the U.S. and International plans were as follows:



	United States Plans						International Plans
	Fiscal year ended March 31,						Fiscal year ended March 31,
	2019		2018		2017		2019	2018	2017
Discount rate	3.9	%	4.1	%	3.9	%	1.4-3.3%	1.5-3.5%	1.8-3.7%
Expected return on plan assets	6.3		6.8		7.0		4.1-6.0	3.6-6.3	3.3-6.5
Rate of compensation increase	N/A		N/A		N/A		1.8-4.0	1.5-4.0	1.5-4.0

Significant Assumptions Used To Determine The Projected Benefit Obligations

Significant assumptions used to determine the projected benefit obligations for the U.S. and International plans were as follows:



	United States Plans				International Plans
	March 31,				March 31,
	2019		2018		2019	2018
Discount rate	3.8	%	3.9	%	1.0-2.7%	1.4-3.3%
Rate of compensation increase	N/A		N/A		2.0-4.0	1.8-4.0

Summary Of Pension Plan Investments Measured At Fair Value

The following table represents the Company's pension plan investments measured at fair value as of March 31, 2019 and 2018 and the basis for that measurement:



	March 31, 2019
	United States Plans								International Plans
	Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Asset category:
Cash and cash equivalents	$	1,080	$	1,080	$	—	$	—	$	83	$	83	$	—	$	—
Equity securities
US^(a)	8,275		8,275		—		—		—		—		—		—
International^(b)	—		—		—		—		23,875		—		23,875		—
Fixed income^(c)	4,408		4,408		—		—		12,833		—		12,833		—
Total	$	13,763	$	13,763	$	—	$	—	$	36,791	$	83	$	36,708	$	—



	March 31, 2018
	United States Plans								International Plans
	Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Asset category:
Cash and cash equivalents	$	891	$	891	$	—	$	—	$	49	$	49	$	—	$	—
Equity securities
US^(a)	9,864		9,864		—		—		—		—		—		—
International^(b)	—		—		—		—		25,768		—		25,768		—
Fixed income^(c)	3,173		3,173		—		—		12,940		—		12,940		—
Total	$	13,928	$	13,928	$	—	$	—	$	38,757	$	49	$	38,708	$	—

The fair values presented above were determined based on valuation techniques to measure fair value as discussed in Note 1.


(a)	US equities include companies that are well diversified by industry sector and equity style (i.e., growth and value strategies). Active and passive management strategies are employed. Investments are primarily in large capitalization stocks and, to a lesser extent, mid- and small-cap stocks.


(b)	International equities are invested in companies that are traded on exchanges outside the U.S. and are well diversified by industry sector, country and equity style. Active and passive strategies are employed. The vast majority of the investments are made in companies in developed markets with a small percentage in emerging markets.

(c)

Fixed income consists primarily of investment grade bonds from diversified industries.

Summary Of Estimated Future Benefit Payments

Estimated future benefit payments under the Company’s pension plans are as follows:




2020	$	2,713
2021	2,783
2022	3,072
2023	3,392
2024	3,536
Years 2025-2029	21,106

Stockholders' Equity and Noncontrolling Interests (Tables)

12 Months Ended

Mar. 31, 2019

Stockholders' Equity and Noncontrolling Interests [Abstract]

Change in Number of Shares of Common Stock Outstanding

The following summarizes the change in the number of shares of common stock outstanding during fiscal years ended March 31, 2017, 2018 and 2019, respectively:




Shares outstanding as of March 31, 2016	43,189,502
Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes	258,034
Shares outstanding as of March 31, 2017	43,447,536
Purchase of treasury stock	(1,756,831	)
Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes	224,295
Shares outstanding as of March 31, 2018	41,915,000
Purchase of treasury stock	(726,347	)
Shares issued towards purchase consideration of Alpha acquisition	1,177,630
Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes	254,467
Shares outstanding as of March 31, 2019	42,620,750

Components Of Accumulated Other Comprehensive Income

The components of AOCI, net of tax, are as follows:



	Beginning Balance			Before Reclassifications			Amount Reclassified from AOCI			Ending Balance
March 31, 2019
Pension funded status adjustment	$	(22,503	)	$	339		$	1,373		$	(20,791	)
Net unrealized gain (loss) on derivative instruments	(3,425		)	(8,396		)	11,691			(130		)
Foreign currency translation adjustment	(15,789		)	(105,972		)	—			(121,761		)
Accumulated other comprehensive loss	$	(41,717	)	$	(114,029	)	$	13,064		$	(142,682	)
March 31, 2018
Pension funded status adjustment	$	(25,555	)	$	1,692		$	1,360		$	(22,503	)
Net unrealized gain (loss) on derivative instruments	1,975			(2,868		)	(2,532		)	(3,425		)
Foreign currency translation adjustment	(129,244		)	113,455			—			(15,789		)
Accumulated other comprehensive loss	$	(152,824	)	$	112,279		$	(1,172	)	$	(41,717	)
March 31, 2017
Pension funded status adjustment	$	(21,861	)	$	(4,659	)	$	965		$	(25,555	)
Net unrealized gain (loss) on derivative instruments	388			5,523			(3,936		)	1,975
Foreign currency translation adjustment	(75,876		)	(53,368		)	—			(129,244		)
Accumulated other comprehensive loss	$	(97,349	)	$	(52,504	)	$	(2,971	)	$	(152,824	)

Reclassification out of Accumulated Other Comprehensive Income

The following table presents reclassifications from AOCI during the twelve months ended March 31, 2019:



Components of AOCI	Amounts Reclassified from AOCI			Location of (Gain) Loss Recognized on Income Statement
Derivatives in Cash Flow Hedging Relationships:
Net unrealized loss on derivative instruments	$	15,281		Cost of goods sold
Tax benefit	(3,590		)
Net unrealized loss on derivative instruments, net of tax	$	11,691

Defined benefit pension costs:
Prior service costs and deferrals	$	1,704		Net periodic benefit cost, included in other (income) expense, net - See Note 1 and 14
Tax benefit	(331		)
Net periodic benefit cost, net of tax	$	1,373

Summary of Redeemable Noncontrolling Interests

The following demonstrates the change in redeemable noncontrolling interests during the fiscal year ended March 31, 2017:




Balance as of March 31, 2016	$	5,997
Net losses attributable to redeemable noncontrolling interests	(2,021		)
Deconsolidation of joint venture	(4,035		)
Foreign currency translation adjustment	59
Balance as of March 31, 2017	$	—

Stock-Based Compensation (Tables)

12 Months Ended

Mar. 31, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary Of Stock Option Activity

The following table summarizes the Company’s stock option activity in the years indicated:



	Number of Options		Weighted- Average Remaining Contract Term (Years)	Weighted- Average Exercise Price		Aggregate Intrinsic Value
Options outstanding as of March 31, 2016	210,297		8.5	$	67.54	$	218
Granted	242,068			57.60		—
Exercised	(263	)		18.25		12
Expired	(434	)		18.25		15
Options outstanding as of March 31, 2017	451,668		8.4	$	62.29	$	7,520
Granted	169,703			83.14		—
Exercised	(62,197	)		63.44		1,132
Forfeited	(11,495	)		70.22		75
Expired	(2,089	)		18.25		137
Options outstanding as of March 31, 2018	545,590		8.4	$	68.65	$	2,679
Granted	192,700			75.17		—
Exercised	(171,630	)		63.66		2,707
Forfeited	(11,754	)		75.17		—
Options outstanding as of March 31, 2019	554,906		8.0	$	72.31	$	1,040
Options exercisable as of March 31, 2019	186,823		6.9	$	69.34	$	452
Options vested and expected to vest, as of March 31, 2019	545,299		8.0	$	72.24	$	1,038

Summary Of Information Regarding Stock Options Outstanding And Exercisable

The following table summarizes information regarding stock options outstanding as of March 31, 2019:




Range of Exercise Prices	Number of Options	Weighted- Average Remaining Contractual Life (Years)	Weighted- Average Exercise Price
$55.00-$60.00	137,599	7.1	$	57.60
$65.01-$70.00	73,368	5.8	$	68.82
$75.01-$83.14	343,939	8.8	$	78.95
	554,906	8.0	$	72.31

Summary Of The Changes In Restricted Stock Units And Market Share Units



	Restricted Stock Units (RSU)				Market condition-based Share Units (TSR)				Performance condition-based Share Units (PSU)
	Number of RSU		Weighted- Average Grant Date Fair Value		Number of TSR		Weighted- Average Grant Date Fair Value		Number of PSU		Weighted- Average Grant Date
Non-vested awards as of March 31, 2018	633,751		$	56.60	349,941		$	70.22	—		$	—
Granted	241,105		69.43		36,646		85.84		45,883		68.48
Stock dividend	6,087		56.81		3,131		72.60		320		68.48
Performance factor	—		—		143		75.48		—		—
Vested	(148,487	)	68.55		(3,482	)	59.94		—		—
Canceled	(10,809	)	72.56		(33,795	)	62.21		(3,677	)	68.48
Non-vested awards as of March 31, 2019	721,647		$	57.72	352,584		$	72.83	42,526		$	68.48

Earnings Per Share (Tables)

12 Months Ended

Mar. 31, 2018

Reconciliation From Basic To Diluted Average Common Shares And Net Earnings Per Common Share



	Fiscal year ended March 31,
	2019		2018		2017
Net earnings attributable to EnerSys stockholders	$	160,239	$	119,594	$	160,214
Weighted-average number of common shares outstanding:
Basic	42,335,023		42,612,036		43,389,333
Dilutive effect of:
Common shares from exercise and lapse of equity awards, net of shares assumed reacquired	673,929		507,820		623,210
Diluted weighted-average number of common shares outstanding	43,008,952		43,119,856		44,012,543
Basic earnings per common share attributable to EnerSys stockholders	$	3.79	$	2.81	$	3.69
Diluted earnings per common share attributable to EnerSys stockholders	$	3.73	$	2.77	$	3.64
Anti-dilutive equity awards not included in diluted weighted-average common shares	355,728		59,482		1,295

Restructuring Plans and Other Exit Charges (Tables)

12 Months Ended

Mar. 31, 2019

Restructuring and Related Activities [Abstract]

Acquisition And Non-Acquisition Related Restructuring Reserve

A roll-forward of the restructuring reserve is as follows:



	Employee Severance			Other			Total
Balance at March 31, 2016	$	2,964		$	25		$	2,989
Accrued	4,566			742			5,308
Costs incurred	(4,754		)	(604		)	(5,358		)
Foreign currency impact and other	(108		)	(19		)	(127		)
Balance at March 31, 2017	$	2,668		$	144		$	2,812
Accrued	4,757			445			5,202
Costs incurred	(4,849		)	(574		)	(5,423		)
Foreign currency impact and other	317			1			318
Balance at March 31, 2018	$	2,893		$	16		$	2,909
Accrued	6,554			1,639			8,193
Costs incurred	(6,893		)	(1,086		)	(7,979		)
Foreign currency impact and other	(198		)	27			(171		)
Balance at March 31, 2019	$	2,356		$	596		$	2,952

Warranty (Tables)

12 Months Ended

Mar. 31, 2019

Analysis Of Changes In Liability For Product Warranties

As warranty estimates are forecasts that are based on the best available information, primarily historical claims experience, claims costs may ultimately differ from amounts provided. An analysis of changes in the liability for product warranties is as follows:



	Fiscal year ended March 31,
	2019			2018			2017
Balance at beginning of year	$	50,602		$	46,116		$	48,422
Current year provisions	23,679			21,706			17,852
Costs incurred	(25,053		)	(18,820		)	(15,945		)
Warranty reserves of acquired business - Alpha	7,535			—			—
Foreign currency translation adjustment	(2,195		)	1,600			(4,213		)
Balance at end of year	$	54,568		$	50,602		$	46,116

Other (Income) Expense, Net (Tables)

12 Months Ended

Mar. 31, 2019

Summary Of Other (Income) Expense, Net

Other (income) expense, net consists of the following:



	Fiscal year ended March 31,
	2019			2018		2017
Foreign exchange transaction (gains) losses	$	(3,044	)	$	5,499	$	(662	)
Non-service components of pension expense	1,502			1,464		1,252
Other	928			556		1,631
Total	$	(614	)	$	7,519	$	2,221

Business Segments (Tables)

12 Months Ended

Mar. 31, 2019

Summary Of Financial Information Related To The Company's Business Segments

Summarized financial information related to the Company’s reportable segments at March 31, 2019, 2018 and 2017 and for each of the fiscal years then ended is shown below.



	Fiscal year ended March 31,
	2019			2018			2017
Net sales by segment to unaffiliated customers
Americas	$	1,690,912		$	1,429,888		$	1,332,353
EMEA	860,563			849,420			763,013
Asia	256,542			302,583			271,783
Total net sales	$	2,808,017		$	2,581,891		$	2,367,149
Net sales by product line
Reserve power	$	1,416,173		$	1,247,900		$	1,142,327
Motive power	1,391,844			1,333,991			1,224,822
Total net sales	$	2,808,017		$	2,581,891		$	2,367,149
Intersegment sales
Americas	$	28,753		$	29,513		$	26,039
EMEA	123,274			133,164			93,150
Asia	34,531			23,375			22,584
Total intersegment sales⁽¹⁾	$	186,558		$	186,052		$	141,773
Operating earnings by segment
Americas	$	186,814		$	189,466		$	191,801
EMEA	71,963			77,671			77,376
Asia	3,213			12,647			14,994
Inventory step up to fair value relating to acquisition - Americas	(7,263		)	—			—
Inventory adjustment relating to exit activities - Americas	—			(3,457		)	—
Inventory adjustment relating to exit activities - EMEA	(2,590		)	—			(2,157		)
Inventory adjustment relating to exit activities - Asia	(526		)	—			—
Restructuring charges - Americas	(4,066		)	(1,246		)	(892		)
Restructuring and other exit charges - EMEA	(26,989		)	(4,023		)	(5,487		)
Restructuring charges - Asia	(3,654		)	(212		)	(781		)
Impairment of goodwill and indefinite-lived intangibles - Americas	—			—			(9,346		)
Impairment of goodwill and indefinite-lived intangibles - EMEA	—			—			(4,670		)
Legal proceedings charge, net - EMEA	(4,437		)	—			(23,725		)
Total operating earnings⁽²⁾	$	212,465		$	270,846		$	237,113
Property, plant and equipment, net
Americas	$	257,559		$	210,998		$	190,169
EMEA	94,932			118,263			100,042
Asia	56,948			60,999			58,338
Total	$	409,439		$	390,260		$	348,549
Capital Expenditures
Americas	$	45,029		$	46,905		$	34,809
EMEA	18,972			18,392			13,733
Asia	6,371			4,535			1,530
Total	$	70,372		$	69,832		$	50,072
Depreciation and Amortization
Americas	$	40,675		$	30,421		$	30,204
EMEA	15,128			16,198			15,693
Asia	7,545			7,698			8,048
Total	$	63,348		$	54,317		$	53,945


(1)	Intersegment sales are presented on a cost-plus basis which takes into consideration the effect of transfer prices between legal entities.

(2)

The Company does not allocate interest expense or other (income) expense, net, to the reportable segments.

Quarterly Financial Data (Tables)

12 Months Ended

Mar. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Summary Of Interim Financial Information



	1st Quarter		2nd Quarter		3rd Quarter			4th Quarter		Fiscal Year
Fiscal year ended March 31, 2019
Net sales	$	670,930	$	660,462	$	680,022		$	796,603	$	2,808,017
Gross profit	165,334		160,880		164,546			202,266		693,026
Operating earnings^(1)(3)(5)	64,179		63,357		49,951			34,978		212,465
Net earnings⁽⁶⁾	46,020		47,447		48,614			18,546		160,627
Net earnings attributable to EnerSys stockholders	45,860		47,424		48,417			18,538		160,239
Net earnings per common share attributable to EnerSys stockholders—basic	$	1.09	$	1.13	$	1.14		$	0.43	$	3.79
Net earnings per common share attributable to EnerSys stockholders—diluted	$	1.08	$	1.11	$	1.12		$	0.42	$	3.73
Fiscal year ended March 31, 2018
Net sales	$	622,625	$	617,289	$	658,935		$	683,042	$	2,581,891
Gross profit	163,458		160,248		167,310			167,388		658,404
Operating earnings⁽²⁾⁽⁴⁾	69,972		64,364		68,785			67,725		270,846
Net earnings (loss)⁽⁷⁾	48,322		43,151		(25,779		)	54,139		119,833
Net earnings (loss) attributable to EnerSys stockholders	48,201		43,222		(25,847		)	54,018		119,594
Net earnings (loss) per common share attributable to EnerSys stockholders—basic	$	1.11	$	1.01	$	(0.61	)	$	1.29	$	2.81
Net earnings (loss) per common share attributable to EnerSys stockholders—diluted	$	1.09	$	1.00	$	(0.61	)	$	1.27	$	2.77


(1)	Included in Operating earnings were inventory adjustment relating to exit activities of $526 and $2,590 in the first and fourth quarter of fiscal 2019, respectively. Also included were inventory adjustments relating to Alpha acquisition of $3,747 and $3,516 in the third and fourth quarter of fiscal 2019, respectively.


(2)	Included in Operating earnings were inventory adjustment relating to exit activities of $3,457 in the fourth quarter of fiscal 2018, respectively.


(3)	Included in Operating earnings were restructuring and other exit charges of $1,739, $1,121, $5,392 and $26,457 for the first, second, third and fourth quarters of fiscal 2019, respectively.


(4)	Included in Operating earnings were restructuring and other exit charges of $833, $1,776, $1,808 and $1,064 for the first, second, third and fourth quarters of fiscal 2018, respectively.


(5)	Included in Operating earnings were legal proceedings settlement income of $2,843 in the third quarter and expense of $7,280 in the fourth quarter of fiscal 2019.


(6)	Included in net earnings was a tax benefit of $13,483 for the third quarter of fiscal 2019, on account of the Tax Act.

(7)

Included in net earnings (loss) was tax expense of $77,347 and $4,106 for the third and fourth quarters of fiscal 2018, respectively, on account of the Tax Act.

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended								12 Months Ended
	Mar. 31, 2019 USD ($)	Dec. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jul. 01, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Oct. 01, 2017 USD ($)	Jul. 02, 2017 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($) segment shares	Mar. 31, 2017 USD ($)	Apr. 01, 2019 USD ($)	Apr. 01, 2018 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents include all highly liquid investments with an original maturity, when purchased, in months										3 months
Number of geographical regions \| segment										3
Reclassification of goodwill impairment									$ 0	$ 0	$ 12,216,000
Revenue	$ 796,603,000	$ 680,022,000	$ 660,462,000	$ 670,930,000	$ 683,042,000	$ 658,935,000	$ 617,289,000	$ 622,625,000	2,808,017,000	2,581,891,000	$ 2,367,149,000
Revenue recognized									6,132,000
Contract liability, current	15,162,000								15,162,000
Contract liability, noncurrent	6,360,000								6,360,000
Contract assets	38,778,000				$ 0				38,778,000	$ 0
Anticipated value of right of return assets	2,667,000								2,667,000
Refund liability	$ 5,153,000								5,153,000
Restricted Stock and Restricted Stock Units
Summary Of Significant Accounting Policies [Line Items]
Percentage of restricted stock units granted, vested per year										25.00%
Vesting period, in years										4 years
Services
Summary Of Significant Accounting Policies [Line Items]
Revenue									$ 157,236,000
Minimum
Summary Of Significant Accounting Policies [Line Items]
Percentage of investment ownership, consolidated	50.00%								50.00%
Percentage of investment ownership, equity method	20.00%								20.00%
Estimated useful lives of finite-lived assets										3 years
Market share units converted into common stock for each unit \| shares										0
Minimum \| Reserve Power Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period										1 year
Minimum \| Motive Power Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period										1 year
Minimum \| Building and Improvements
Summary Of Significant Accounting Policies [Line Items]
Property, plant, and equipment, useful life										10 years
Minimum \| Machinery and Equipment
Summary Of Significant Accounting Policies [Line Items]
Property, plant, and equipment, useful life										3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Percentage of investment ownership, equity method	50.00%								50.00%
Percentage of investment ownership, cost method	20.00%								20.00%
Estimated useful lives of finite-lived assets										20 years
Market share units converted into common stock for each unit \| shares										2
Maximum \| Reserve Power Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period										20 years
Maximum \| Motive Power Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period										7 years
Maximum \| Building and Improvements
Summary Of Significant Accounting Policies [Line Items]
Property, plant, and equipment, useful life										33 years
Maximum \| Machinery and Equipment
Summary Of Significant Accounting Policies [Line Items]
Property, plant, and equipment, useful life										15 years
Transferred over Time
Summary Of Significant Accounting Policies [Line Items]
Revenue recognized									$ 100,809,000
Accounting Standards Update 2016-02 [Member] \| Scenario, Forecast [Member]
Summary Of Significant Accounting Policies [Line Items]
Expected lease liability to be recognized												$ 100,000,000
Difference between Revenue Guidance in Effect before and after Topic 606 \| Accounting Standards Update 2014-09
Summary Of Significant Accounting Policies [Line Items]
Contract liability, current													$ 9,387,000
Contract liability, noncurrent													7,094,000
Contract assets													$ 24,810,000

Summary of Significant Accounting Policies - Remaining Performance Obligation (Detail) $ in Thousands	Mar. 31, 2019 USD ($)
Accounting Policies [Abstract]
Remaining performance obligation	$ 66,088
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-04-01
Accounting Policies [Abstract]
Remaining performance obligation	$ 60,443
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Accounting Policies [Abstract]
Remaining performance obligation	$ 5,645
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year

Acquisitions - Additional Information (Detail)		9 Months Ended	12 Months Ended
Acquisitions - Additional Information (Detail)	Dec. 07, 2018 USD ($) $ / shares shares	Dec. 30, 2018 USD ($)	Mar. 31, 2019 USD ($) shares	Mar. 31, 2018 USD ($) acquisition	Mar. 31, 2017 USD ($) acquisition
Business Acquisition [Line Items]
Number of businesses acquired \| acquisition				0	0
Purchase of businesses			$ 654,614,000	$ 2,988,000	$ 12,392,000
Goodwill relating to acquisitions			320,618,000	3,670,000
Estimated tax-deductible goodwill			$ 58,699,000	$ 18,147,000
Shares issued in acquisition (in shares) \| shares			1,177,630
Closing day spot rate (USD per share) \| $ / shares	$ 79.20
Alpha
Business Acquisition [Line Items]
Initial purchase consideration	$ 750,000,000
Consideration transferred	742,502,000
Acquisition cost expensed			$ 12,883,000
Estimated tax-deductible goodwill			42,262,000
Inventory adjustment			7,263,000
Payments to acquire businesses	650,000,000
Shares issued in acquisition, value	93,268,000
Working capital adjustment	$ 766,000
Shares issued in acquisition (USD per share) \| $ / shares	$ 84.92
Revenues and gains recognized in acquisition			162,454,000
Expenses and losses recognized in acquisition			1,252,000
Alpha \| Customer relationships
Business Acquisition [Line Items]
Acquired intangible assets	$ 221,000,000
Minimum
Business Acquisition [Line Items]
Estimated useful lives of finite-lived assets				3 years
Maximum
Business Acquisition [Line Items]
Consideration transferred		$ 250,000,000
Estimated useful lives of finite-lived assets				20 years
Trademarks \| Alpha
Business Acquisition [Line Items]
Acquired indefinite-lived intangible assets	$ 56,000,000
Common Stock \| Alpha
Business Acquisition [Line Items]
Shares issued in acquisition (in shares) \| shares	1,177,630
Operating Expense \| Alpha
Business Acquisition [Line Items]
Acquisition cost expensed			$ 12,883,000

Acquisitions Acquisitions - Assets and Liabilities Acquired (Details) - USD ($) $ in Thousands	Dec. 07, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Business Acquisition [Line Items]
Goodwill		$ 656,399	$ 352,805	$ 328,657
Alpha
Business Acquisition [Line Items]
Accounts receivable	$ 115,467
Inventories	84,297
Other current assets	6,822
Other intangible assets	332,000
Property, plant and equipment	20,987
Other assets	9,005
Total assets acquired	568,578
Accounts payable	35,803
Accrued liabilities	41,918
Deferred income taxes	56,331
Other liabilities	12,642
Total liabilities assumed	146,694
Net assets acquired	421,884
Cash paid for net assets acquired	650,000
Shares issued in acquisition, value	93,268
Working capital adjustment	(766)
Consideration transferred	742,502
Goodwill	$ 320,618

Acquisitions - Summary of Intangible Assets (Details) - Alpha $ in Thousands	Dec. 07, 2018 USD ($)
Business Acquisition [Line Items]
Other intangible assets	$ 332,000
Customer relationships
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	14 years
Acquired intangible assets	$ 221,000
Technology
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Acquired intangible assets	$ 55,000
Trademarks
Business Acquisition [Line Items]
Acquired indefinite-lived intangible assets	$ 56,000

Acquisitions - Pro Forma Information (Details) - Alpha - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition [Line Items]
Net sales	$ 3,278,646	$ 3,124,527
Net earnings attributable to EnerSys stockholders	$ 207,904	$ 126,965
Net earnings per share attributable to EnerSys stockholders - basic	$ 4,790	$ 2,900
Net earnings per share attributable to EnerSys stockholders - assuming dilution	$ 4,710	$ 2,870

Inventories - Summary of Inventories (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 138,718	$ 92,216
Work-in-process	129,736	136,068
Finished goods	235,415	185,950
Total	$ 503,869	$ 414,234

Property, Plant, and Equipment - Summary of PPE (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Property, Plant and Equipment [Abstract]
Land, buildings, and improvements	$ 268,006	$ 273,506
Machinery and equipment	683,955	657,262
Construction in progress	54,278	49,900
Property, Plant and Equipment, Gross, Total	1,006,239	980,668
Less accumulated depreciation	(596,800)	(590,408)
Total	$ 409,439	$ 390,260	$ 348,549

Property, Plant, and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 48,618	$ 45,874	$ 45,388
Interest capitalized	$ 1,581	$ 1,082	$ 817

Goodwill and Other Intangible Assets - Schedule of Companys Other Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Intangible Assets [Line Items]
Gross Amount, Total	$ 523,432	$ 193,532
Accumulated Amortization ,Total	(61,116)	(46,391)
Net Amount ,Total	462,316	147,141
Trademarks
Intangible Assets [Line Items]
Indefinite-lived intangible assets, Gross Amount	152,484	97,444
Finite-lived intangible assets, Gross Amount	2,003	2,003
Indefinite-lived intangible assets, Accumulated Amortization	(953)	(953)
Finite-lived intangible assets, Accumulated Amortization	(1,236)	(1,151)
Indefinite-lived intangible assets, Net Amount	151,531	96,491
Finite-lived intangible assets, Net Amount	767	852
Customer relationships
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	286,664	66,973
Finite-lived intangible assets, Accumulated Amortization	(42,704)	(31,500)
Finite-lived intangible assets, Net Amount	243,960	35,473
Noncompete Agreements
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	3,025	2,852
Finite-lived intangible assets, Accumulated Amortization	(2,807)	(2,759)
Finite-lived intangible assets, Net Amount	218	93
Patents
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	77,779	22,769
Finite-lived intangible assets, Accumulated Amortization	(12,229)	(8,872)
Finite-lived intangible assets, Net Amount	65,550	13,897
Licenses
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	1,477	1,491
Finite-lived intangible assets, Accumulated Amortization	(1,187)	(1,156)
Finite-lived intangible assets, Net Amount	$ 290	$ 335

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Mar. 05, 2019	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value		$ 725,576	$ 421,982
Amortization expense, related to finite-lived intangible assets		14,730	8,443	$ 8,557
Expected amortization expense, 2018		29,491
Expected amortization expense, 2019		29,237
Expected amortization expense, 2020		28,993
Expected amortization expense, 2021		27,694
Expected amortization expense, 2022		24,287
Impairment of goodwill		0	0	12,216
Asset impairment charges	$ 14,958
Estimated tax-deductible goodwill		58,699	18,147
Americas
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value		528,039	209,100
Impairment of goodwill				8,646
Impairment of indefinite-lived intangible assets				700
EMEA
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value		$ 149,422	$ 161,978
Impairment of goodwill				3,570
Impairment of indefinite-lived intangible assets				$ 1,100

Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill by Business Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Goodwill [Roll Forward]
Balance at beginning of year	$ 352,805	$ 328,657
Acquisitions during the year	320,618	3,670
Foreign currency translation adjustment	(17,024)	20,478
Balance at end of year	656,399	352,805
Americas
Goodwill [Roll Forward]
Balance at beginning of year	151,255	146,982
Acquisitions during the year	320,618	3,670
Foreign currency translation adjustment	(1,679)	603
Balance at end of year	470,194	151,255
EMEA
Goodwill [Roll Forward]
Balance at beginning of year	155,825	138,813
Acquisitions during the year	0	0
Foreign currency translation adjustment	(12,556)	17,012
Balance at end of year	143,269	155,825
Asia
Goodwill [Roll Forward]
Balance at beginning of year	45,725	42,862
Acquisitions during the year	0	0
Foreign currency translation adjustment	(2,789)	2,863
Balance at end of year	$ 42,936	$ 45,725

Goodwill and Other Intangible Assets - Schedule of Goodwill and Goodwill Impairment Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Goodwill [Line Items]
Gross carrying value	$ 725,576	$ 421,982
Accumulated goodwill impairment charges	(69,177)	(69,177)
Net book value	656,399	352,805	$ 328,657
Americas
Goodwill [Line Items]
Gross carrying value	528,039	209,100
Accumulated goodwill impairment charges	(57,845)	(57,845)
Net book value	470,194	151,255	146,982
EMEA
Goodwill [Line Items]
Gross carrying value	149,422	161,978
Accumulated goodwill impairment charges	(6,153)	(6,153)
Net book value	143,269	155,825	138,813
Asia
Goodwill [Line Items]
Gross carrying value	48,115	50,904
Accumulated goodwill impairment charges	(5,179)	(5,179)
Net book value	$ 42,936	$ 45,725	$ 42,862

Prepaid and Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Contract assets	$ 38,778	$ 0
Prepaid income taxes	9,608	8,921
Other	27,732	21,319
Total	$ 109,431	$ 56,910

Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Payables and Accruals [Abstract]
Payroll and benefits	$ 54,285	$ 50,053
Accrued selling expenses	35,394	34,831
Warranty	21,646	22,637
Project related accruals	16,301	0
Contract liabilities	15,162	0
Income taxes payable	9,234	19,696
Tax Act - Transition Tax	5,290	7,800
Restructuring	2,952	2,909
Pension	1,207	1,657
Other	48,356	27,095
Total	$ 255,881	$ 214,118

Debt - Long Term Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018	Dec. 27, 2015
Debt Instrument [Line Items]
Unamortized Debt Issuance Expense	$ (5,559)	$ (5,965)
Debt and Capital Lease Obligations	977,315	585,500
Long-term Debt and Capital Lease Obligations, Current	0	0
Long-term Debt and Capital Lease Obligations	971,756	579,535
Senior Unsecured 5.00% Due 2028
Debt Instrument [Line Items]
Long-term debt	300,000	300,000	$ 300,000
Unamortized Debt Issuance Expense	(2,497)	(3,122)
Incremental Commitment Agreement [Member] \| Secured Debt [Member] \| 2017 Revolver borrowings
Debt Instrument [Line Items]
Line of Credit Facility, Incremental Term Loan Commitment	677,315	285,500
Unamortized Debt Issuance Expense	$ (3,062)	$ (2,843)

Debt - Long Term Debt (Phantom) (Detail)	12 Months Ended
Debt - Long Term Debt (Phantom) (Detail)	Mar. 31, 2019
Senior Unsecured 3.375% Convertible Notes Due 2038
Debt Instrument [Line Items]
Interest rate of debt instrument	3.375%
Maturity year	2038
2011 Credit Facility Due 2018
Debt Instrument [Line Items]
Maturity year	2018

Debt - Additional Information (Detail)			9 Months Ended	12 Months Ended
Debt - Additional Information (Detail)	Aug. 04, 2017 USD ($)	Jul. 08, 2014	Dec. 30, 2018 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Dec. 07, 2018 USD ($)	Dec. 07, 2018 CAD ($)	Sep. 30, 2018	Aug. 03, 2017 USD ($)	Apr. 23, 2015 USD ($)
Debt Instrument [Line Items]
Line of Credit Facility, Increase in Borrowing Capacity Limit	$ 325,000,000
Company owned capital stock percentage	65.00%
Long-term Debt and Capital Lease Obligations, Current				$ 0	$ 0
Long-term Debt, Weighted Average Interest Rate, at Point in Time				4.10%	3.70%
Short term borrowing outstanding amount				$ 54,490,000	$ 18,341,000
Short-term debt, weighted-average interest rates				4.00%
Payments of Debt Issuance Costs				$ 1,393,000	2,677,000
Write off of Deferred Debt Issuance Cost				483,000	301,000
Deferred financing fees, net of accumulated amortization				5,559,000	5,965,000
Amortization expense included in interest expense				$ 1,316,000	1,302,000	$ 1,388,000
2011 Credit Facility Due 2018
Debt Instrument [Line Items]
Debt instrument maturity year				2018
Convertible Notes Payable
Debt Instrument [Line Items]
Available lines of credit				$ 546,960,000	613,234,000
Stand by letters of credit				3,955,000	3,074,000
Line of Credit Facility, Remaining Borrowing Capacity, Uncommitted Portion				$ 87,685,000	150,459,000
Senior Unsecured 5.00% Due 2023
Debt Instrument [Line Items]
Long-term debt											$ 300,000,000
Interest rate of debt instrument											5.00%
Senior Unsecured 3.375% Convertible Notes Due 2038
Debt Instrument [Line Items]
Interest rate of debt instrument				3.375%
Debt instrument maturity year				2038
Interest paid				$ 29,552,000	$ 23,527,000	$ 20,781,000
Maximum
Debt Instrument [Line Items]
Consideration transferred			$ 250,000,000
Amended 2017 Term Loan \| Term Loam [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity							$ 99,105,000	$ 133,050,000
Amended 2017 Term Loan \| Secured Debt [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity							449,105,000
Amended 2017 Revolver [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity							700,000,000
2017 Revolver borrowings \| Secured Debt [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity							299,105,000
Face value of debt instrument	$ 150,000,000
Available lines of credit				438,315,000
2017 Revolver borrowings \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	600,000,000						$ 100,000,000
Available lines of credit				239,000,000
Long-term Debt and Capital Lease Obligations, Current				$ 28,098,000
2011 Credit Facility Due 2018 \| Secured Debt [Member]
Debt Instrument [Line Items]
Face value of debt instrument										$ 150,000,000
Available lines of credit	123,750,000
2011 Credit Facility Due 2018 \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity										$ 500,000,000
Available lines of credit	240,000,000
Debt Instrument Quarterly Installments Beginning December 31, 2018 Through December 30, 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment	5,625,000
Debt Instrument Quarterly Installments Beginning December 31, 2019 Through December 30, 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment	8,438,000
Debt Instrument Quarterly Installments Beginning December 31, 2020 Through September 29, 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment	11,250,000
Debt Instrument Final Installments Payable On September 30, 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment	$ 315,000,000
London Interbank Offered Rate (LIBOR) [Member] \| 2017 Revolver And 2017 Term Loan [Member]
Debt Instrument [Line Items]
Interest at a floating rate	1.25%
London Interbank Offered Rate (LIBOR) [Member] \| 2017 Revolver And 2017 Term Loan [Member] \| Minimum
Debt Instrument [Line Items]
Interest at a floating rate	1.25%
London Interbank Offered Rate (LIBOR) [Member] \| 2017 Revolver And 2017 Term Loan [Member] \| Maximum
Debt Instrument [Line Items]
Interest at a floating rate	2.00%
London Interbank Offered Rate (LIBOR) [Member] \| Incremental Commitment Agreement [Member] \| Revolving Commitments and/or Term Loans [Member]
Debt Instrument [Line Items]
Interest at a floating rate						1.25%
London Interbank Offered Rate (LIBOR) [Member] \| Incremental Commitment Agreement [Member] \| Revolving Commitments and/or Term Loans [Member] \| Minimum
Debt Instrument [Line Items]
Interest at a floating rate		1.25%
London Interbank Offered Rate (LIBOR) [Member] \| Incremental Commitment Agreement [Member] \| Revolving Commitments and/or Term Loans [Member] \| Maximum
Debt Instrument [Line Items]
Interest at a floating rate		1.75%
Higher of Bank of America Prime Rate or Federal Funds Effective Rate [Member] \| Incremental Commitment Agreement [Member] \| Revolving Commitments and/or Term Loans [Member] \| Minimum
Debt Instrument [Line Items]
Interest at a floating rate		0.25%
Higher of Bank of America Prime Rate or Federal Funds Effective Rate [Member] \| Incremental Commitment Agreement [Member] \| Revolving Commitments and/or Term Loans [Member] \| Maximum
Debt Instrument [Line Items]
Interest at a floating rate		0.75%
Federal Funds Effective Swap Rate [Member] \| 2017 Revolver And 2017 Term Loan [Member]
Debt Instrument [Line Items]
Interest at a floating rate	0.50%
Eurodollar [Member] \| 2017 Revolver And 2017 Term Loan [Member]
Debt Instrument [Line Items]
Interest at a floating rate	1.00%
CDOR Rate [Member] \| 2017 Revolver And 2017 Term Loan [Member]
Debt Instrument [Line Items]
Interest at a floating rate	0.50%
Measurement Input, Maximum Leverage Ratio [Member]
Debt Instrument [Line Items]
Debt Instrument, Measurement Input			4.00						3.50

Leases - Schedule of Capital and Operating Leases (Detail) $ in Thousands	Mar. 31, 2019 USD ($)
Operating Leases
2019	$ 31,483
2020	24,290
2021	16,514
2022	11,596
2023	8,683
Thereafter	23,757
Total minimum lease payments	$ 116,323

Leases - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Leases [Abstract]
Rental expense	$ 40,261	$ 38,146	$ 35,991

Other Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Other Liabilities Disclosure [Abstract]
Tax Act - Transition Tax	$ 55,489	$ 89,700
Pension	39,924	44,404
Warranty	32,922	27,965
Contract liabilities	0	7,094
Contract liabilities	6,360	0
Other	10,265	10,240
Total	$ 165,200	$ 181,087

Fair Value of Financial Instruments - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	$ (1,151)	$ (3,855)
Lead hedge forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(902)	(3,877)
Foreign currency forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(249)	22
Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(1,151)	(3,855)
Significant Other Observable Inputs (Level 2) \| Lead hedge forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(902)	(3,877)
Significant Other Observable Inputs (Level 2) \| Foreign currency forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	$ (249)	$ 22

Fair Value of Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 05, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 27, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading of convertible notes, face value, disclosed as a percentage		99.00%	102.00%
Fixed asset impairment	$ 14,958
Senior Unsecured 5.00% Due 2028
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt		$ 300,000	$ 300,000	$ 300,000
Fair Value, Measurements, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of fixed assets		$ 242

Fair Value of Financial Instruments - Carrying Amounts and Estimated Fair Values of Company Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives assets, Carrying Amount	$ 0	$ 22
Derivatives liabilities, Carrying Amount	1,151	3,877
Derivatives assets, Fair Value	0	22
Derivatives liabilities, Fair Value	1,151	3,877
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Payable, Fair Value Disclosure	300,000	300,000
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Payable, Fair Value Disclosure	$ 297,000	$ 304,500

Derivative Financial Instruments - Additional Information (Detail) $ in Thousands, lb in Millions	12 Months Ended
	Mar. 31, 2019 USD ($) lb	Mar. 31, 2018 USD ($) lb
Derivatives, Fair Value [Line Items]
Foreign currency contract, maturity	1 year
Cost of Sales
Derivatives, Fair Value [Line Items]
Derivative gain (loss) to be recorded in income within 12 months, before tax	$ 46
Lead hedge forward contracts
Derivatives, Fair Value [Line Items]
Hedge forward contracts, maturity	1 year
Derivative, nonmonetary notional amount, mass \| lb	42.0	62.9
Total purchase price of derivative	$ 39,218	$ 72,207
Designated as Hedging Instrument \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Notional amount	42,318	54,164
Not Designated as Hedging Instrument \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Notional amount	$ 22,201	$ 28,486

Derivative Financial Instruments - Fair Value of Derivative Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	$ 0	$ 22
Derivatives liabilities, Fair Value	1,151	3,877
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	0	209
Derivatives liabilities, Fair Value	910	3,877
Designated as Hedging Instrument \| Prepaid and other current assets \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	0	209
Designated as Hedging Instrument \| Accrued expenses \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivatives liabilities, Fair Value	8	0
Designated as Hedging Instrument \| Accrued expenses \| Lead hedge forward contracts
Derivatives, Fair Value [Line Items]
Derivatives liabilities, Fair Value	902	3,877
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	0	0
Derivatives liabilities, Fair Value	241	187
Not Designated as Hedging Instrument \| Prepaid and other current assets \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	0	0
Not Designated as Hedging Instrument \| Accrued expenses \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivatives liabilities, Fair Value	241	187
Not Designated as Hedging Instrument \| Accrued expenses \| Lead hedge forward contracts
Derivatives, Fair Value [Line Items]
Derivatives liabilities, Fair Value	$ 0	$ 0

Derivative Financial Instruments - Effect of Derivative Instruments on Consolidated Condensed Statements of Income (Detail) - Designated as Hedging Instrument - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	$ (10,980)	$ (4,329)	$ 8,752
Gain (Loss) Reclassified from AOCI (Effective Portion)	(15,281)	3,142	6,236
Lead hedge forward contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	(12,531)	(805)	7,907
Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	1,551	(3,524)	845
Cost of Sales \| Lead hedge forward contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Reclassified from AOCI (Effective Portion)	(15,666)	5,860	5,803
Cost of Sales \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Reclassified from AOCI (Effective Portion)	$ 385	$ (2,718)	$ 433

Derivative Financial Instruments - Effect of Derivative Instruments (Detail) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ (1,856)	$ 180	$ (471)
Other (Income) Expense \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ (1,856)	$ 180	$ (471)

Income Taxes - Schedule of Income Tax Expense (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 30, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Current:
Federal		$ 6,377,000	$ 115,315,000	$ 30,362,000
State		5,027,000	3,461,000	4,855,000
Foreign		16,636,000	20,030,000	17,800,000
Total current income tax expense		28,040,000	138,806,000	53,017,000
Deferred income tax (benefit) expense
Federal		(5,031,000)	(9,551,000)	857,000
State		(669,000)	789,000	590,000
Foreign		(756,000)	(11,551,000)	8,000
Total deferred income tax (benefit) expense		(6,456,000)	(20,313,000)	1,455,000
Income tax expense	$ 13,483	$ 21,584,000	$ 118,493,000	$ 54,472,000

Income Taxes - Schedule of Earning Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
United States	$ 53,339	$ 74,440	$ 80,436
Foreign	128,872	163,886	132,259
Earnings before income taxes	$ 182,211	$ 238,326	$ 212,695

Income Taxes - Additional Information (Detail) - USD ($)		3 Months Ended			12 Months Ended
	Dec. 22, 2017	Dec. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Income Tax Contingency [Line Items]
Income taxes paid						$ 53,866,000	$ 28,044,000	$ 45,332,000
Blended rate					21.00%	31.55%	35.00%	35.00%
Impact of Tax Act			$ 4,106,000	$ 77,347,000	$ (13,483,000)	$ 83,400,000	$ 0
Provisional Transition Tax liability	$ 97,500,000
Tax Act - Transition Tax			7,800,000		5,290,000	7,800,000
Tax Act - Transition Tax			89,700,000		55,489,000	89,700,000
Net operating loss carryforwards carried forward indefinitely					102,792,000
Net operating loss carryforwards subject to expiration					(66,114,000)
Valuation allowance			15,255,000		17,519,000	15,255,000
Income Tax Expense (Benefit)		$ (13,483)			$ (21,584,000)	$ (118,493,000)	$ (54,472,000)
Effective income tax rates						11.90%	49.70%	25.60%
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent					12.30%	5.20%	13.50%
Income (Loss) from Continuing Operations before Income Taxes, Foreign					$ 128,872,000	$ 163,886,000	$ 132,259,000
Undistributed earnings of foreign subsidiaries			1,167,000,000			1,167,000,000	$ 1,260,000,000
Estimated change in unrecognized tax benefit in fiscal 2015					2,275,000
Tax related interest and penalties					$ 75,000	$ 116,000
Tax Rate of Swiss Subsidiary					4.00%	8.00%	5.00%
Income tax expense (benefit)					$ 13,483,000
Domestic Tax Authority
Income Tax Contingency [Line Items]
Increase (decrease) in tax rate					2.20%
Foreign
Income Tax Contingency [Line Items]
United States federal net operating loss carryforwards					$ 168,906,000
Valuation allowance			13,730,000		15,594,000	$ 13,730,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount					1,864,000
Income Tax Expense (Benefit)					$ 2,876,000
Increase (decrease) in tax rate					(0.90%)
Federal
Income Tax Contingency [Line Items]
United States federal net operating loss carryforwards					$ 1,438,000
Net operating loss carryforwards subject to expiration					630,000
Valuation allowance			630,000		1,027,000	630,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount					397,000
State
Income Tax Contingency [Line Items]
United States federal net operating loss carryforwards					33,900,000
Valuation allowance			$ 895,000		898,000	$ 895,000
Foreign Currency Translation Adjustment And Offset Adjustment To Net Operating Losses \| Foreign
Income Tax Contingency [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount					1,012,000
Alpha \| Federal
Income Tax Contingency [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount					$ 1,027,000

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Deferred tax assets:
Accounts receivable	$ 1,297	$ 1,790
Inventories	4,081	3,660
Net operating loss carryforwards	48,423	50,928
Accrued expenses	21,574	21,274
Deferred Tax Assets, Deferred Expense, Capitalized Research and Development Costs	7,061	0
Other assets	17,656	16,832
Gross deferred tax assets	100,092	94,484
Less valuation allowance	(17,519)	(15,255)
Total deferred tax assets	82,573	79,229
Deferred tax liabilities:
Property, plant and equipment	25,656	21,045
Intangible assets	96,826	46,058
Other liabilities	1,737	1,331
Total deferred tax liabilities	124,219	68,434
Deferred Tax Liabilities, Net	$ (41,646)
Net deferred tax assets		$ 10,795

Income Taxes - Reconciliation of Income Taxes at Statutory Rate (Detail) - USD ($)	3 Months Ended			12 Months Ended
	Dec. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
United States statutory income tax expense				$ 38,264,000	$ 75,196,000	$ 74,444,000
Impact of Tax Act		$ 4,106,000	$ 77,347,000	(13,483,000)	83,400,000	0
State income taxes, net of federal effect				3,285,000	3,146,000	3,677,000
Nondeductible expenses, domestic manufacturing deduction (fiscal 2018 and 2017) and other				2,677,000	1,078,000	1,993,000
Legal proceedings charge - European Competition Investigations - See Note 18				2,405,000	0	7,873,000
Net effect of GILTI, FDII, BEAT				2,320,000	0	0
Goodwill impairment - See Note 5				0	0	3,812,000
Effect of foreign operations				(16,763,000)	(35,048,000)	(39,377,000)
Valuation allowance				2,879,000	(9,279,000)	2,050,000
Income tax expense	$ 13,483			$ 21,584,000	$ 118,493,000	$ 54,472,000

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Reconciliation of Unrecognized Tax Benefits
Unrecognized tax benefits, beginning balance	$ 1,568	$ 1,450	$ 2,375
Increases related to current year tax positions	129	397	252
Increases related to the Alpha acquisition	7,840	0	0
Increases related to prior year tax positions	11,463	11	31
Decreases related to prior tax positions due to foreign currency translation	(544)	0	(352)
Decreases related to prior year tax positions	(93)	(1)	(678)
Lapse of statute of limitations	(198)	(289)	(178)
Unrecognized tax benefits, ending balance	$ 20,165	$ 1,568	$ 1,450

Retirement Plans - Net Periodic Pension Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment	$ (45)	$ (46)	$ (42)
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	371
Interest cost	631	658	664
Expected return on plan assets	(514)	(496)	(816)
Amortization and deferral	184	303	453
Net periodic benefit cost	301	465	672
International Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	997	1,025	871
Interest cost	1,831	1,795	1,848
Expected return on plan assets	(2,151)	(2,264)	(1,875)
Amortization and deferral	1,520	1,468	978
Net periodic benefit cost	$ 2,197	$ 2,024	$ 1,822

Retirement Plans - Change in Projected Benefit Obligations and Change in Plan Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
United States Plans
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at the beginning of the period	$ 16,713	$ 16,682
Service cost	0	0	$ 371
Interest cost	631	658	664
Benefits paid, inclusive of plan expenses	(1,061)	(1,037)
Plan curtailments and settlements	0	0
Experience loss	364	410
Foreign currency translation adjustment	0	0
Benefit obligation at the end of the period	16,647	16,713	16,682
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at the beginning of the period	13,928	12,731
Actual return on plan assets	758	1,731
Employer contributions	138	503
Benefits paid, inclusive of plan expenses	(1,061)	(1,037)
Defined Benefit Plan, Settlements and Curtailments, Plan Assets	0	0
Foreign currency translation adjustment	0	0
Fair value of plan assets at the end of the period	13,763	13,928	12,731
Funded status deficit	(2,884)		(2,785)
International Plans
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at the beginning of the period	82,033	74,478
Service cost	997	1,025	871
Interest cost	1,831	1,795	1,848
Benefits paid, inclusive of plan expenses	(1,758)	(2,153)
Plan curtailments and settlements	(1,130)	(52)
Experience loss	(261)	(2,705)
Foreign currency translation adjustment	(6,674)	9,645
Benefit obligation at the end of the period	75,038	82,033	74,478
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at the beginning of the period	38,757	34,323
Actual return on plan assets	2,109	688
Employer contributions	1,670	1,865
Benefits paid, inclusive of plan expenses	(1,758)	(2,153)
Defined Benefit Plan, Settlements and Curtailments, Plan Assets	(1,130)	(52)
Foreign currency translation adjustment	(2,857)	4,086
Fair value of plan assets at the end of the period	36,791	38,757	$ 34,323
Funded status deficit	$ (38,247)	$ (43,276)

Retirement Plans - Amounts Recognized in Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan amounts recognized in balance sheet	$ (41,131)	$ (46,061)
Accrued expenses
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan amounts recognized in balance sheet	(1,207)	(1,657)
Other liabilities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan amounts recognized in balance sheet	$ (39,924)	$ (44,404)

Retirement Plans - Pension Components Before Tax and Related Changes Net of Tax Recognized in AOCI (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Retirement Benefits [Abstract]
Prior service cost	$ 307	$ 385	$ 377
Net loss	(24,051)	(27,762)	(28,475)
Net amount recognized	$ 24,358	$ 28,147	$ 28,852

Retirement Plans - Summary Changes in Plan Assets and Benefit Obligations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Retirement Benefits [Abstract]
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	$ 0	$ 0	$ 0
Changes in plan assets and benefit obligations:
Net loss (gain) arising during the year	(99)	(1,953)	5,485
Effect of exchange rates on amounts included in AOCI	(1,984)	3,019	(2,275)
Amounts recognized as a component of net periodic benefit costs:
Amortization of prior service cost	(45)	(46)	(42)
Amortization or settlement recognition of net loss	(1,659)	(1,725)	(1,389)
Total recognized in other comprehensive income	$ (3,787)	$ (705)	$ 1,779

Retirement Plans - Summary of Recognized Components of Net Periodic Pension Cost Included in Accumulated Other Comprehensive Income (Detail) $ in Thousands	Mar. 31, 2019 USD ($)
Retirement Benefits [Abstract]
Prior service cost	$ (44)
Net loss	(1,185)
Net amount expected to be recognized	$ (1,229)

Retirement Plans - Summary of Accumulated Benefit Obligation Related to All Defined Pension Plans (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 16,647	$ 16,713
Accumulated benefit obligation	16,647	16,713
Fair value of plan assets	13,763	13,928
International Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	75,038	82,033
Accumulated benefit obligation	71,350	77,724
Fair value of plan assets	36,791	38,757
Unfunded Defined Benefit Plan \| United States Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	0	0
Accumulated benefit obligation	0	0
Unfunded Defined Benefit Plan \| International Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	32,320	33,124
Accumulated benefit obligation	30,328	31,270
Defined Benefit Plans With An Accumulated Benefit Obligation In Excess Of The Fair Value Of Plan Assets \| United States Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	16,647	16,713
Accumulated benefit obligation	16,647	16,713
Fair value of plan assets	13,763	13,928
Defined Benefit Plans With An Accumulated Benefit Obligation In Excess Of The Fair Value Of Plan Assets \| International Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	74,235	81,253
Accumulated benefit obligation	70,654	77,021
Fair value of plan assets	$ 36,077	$ 37,986

Retirement Plans - Significant Assumptions Used to Determine Net Periodic Benefit Cost (Detail)	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.90%	4.10%	3.90%
Expected return on plan assets	6.30%	6.80%	7.00%
International Plans \| Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate		1.40%	1.50%	1.80%
Expected return on plan assets		4.10%	3.60%	3.30%
Rate of compensation increase		1.80%	1.50%	1.50%
International Plans \| Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate		3.30%	3.50%	3.70%
Expected return on plan assets		6.00%	6.30%	6.50%
Rate of compensation increase		4.00%	4.00%	4.00%

Retirement Plans - Significant Assumptions Used to Determine Projected Benefit Obligations (Detail)	Mar. 31, 2019	Mar. 31, 2018
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.80%	3.90%
International Plans \| Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	1.00%	1.40%
Rate of compensation increase	2.00%	1.80%
International Plans \| Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.70%	3.30%
Rate of compensation increase	4.00%	4.00%

Retirement Plans - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Expected cash contributions to pension plans in 2014	$ 1,640
Defined Contribution Pension
Defined Benefit Plan Disclosure [Line Items]
Employer expenses	12,078	$ 8,931	$ 7,447
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Employer expenses	138	503
International Plans
Defined Benefit Plan Disclosure [Line Items]
Employer expenses	$ 1,670	$ 1,865
International Plans \| Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation percentage	65.00%
Minimum \| United States Plans \| Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Equity investments target range, minimum	40.00%
Maximum \| United States Plans \| Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Equity investments target range, minimum	75.00%

Retirement Plans - Summary of Pension Plan Investments Measured at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	$ 13,763	$ 13,928	$ 12,731
United States Plans \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	13,763	13,928
United States Plans \| Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	1,080	891
United States Plans \| Cash and Cash Equivalents \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	1,080	891
United States Plans \| US Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	8,275	9,864
United States Plans \| US Equity Securities \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	8,275	9,864
United States Plans \| International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
United States Plans \| International Equity Securities \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
United States Plans \| Fixed Income Funds
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	4,408	3,173
United States Plans \| Fixed Income Funds \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	4,408	3,173
International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	36,791	38,757	$ 34,323
International Plans \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	83	49
International Plans \| Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	36,708	38,708
International Plans \| Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	83	49
International Plans \| Cash and Cash Equivalents \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	83	49
International Plans \| International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	23,875	25,768
International Plans \| International Equity Securities \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0
International Plans \| International Equity Securities \| Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	23,875	25,768
International Plans \| Fixed Income Funds
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	12,833	12,940
International Plans \| Fixed Income Funds \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0
International Plans \| Fixed Income Funds \| Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	$ 12,833	$ 12,940

Retirement Plans - Summary of Estimated Future Benefit Payments (Detail) $ in Thousands	Mar. 31, 2019 USD ($)
Defined Benefit Plan, Expected Future Benefit Payments, Rolling Maturity [Abstract] (Deprecated 2017-01-31)
2020	$ 2,713
2021	2,783
2022	3,072
2023	3,392
2024	3,536
Years 2025-2029	$ 21,106

Stockholders' Equity and Noncontrolling Interests - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Dec. 07, 2018	Mar. 31, 2019	Mar. 31, 2018
Class of Stock [Line Items]
Nonvested stock, weighted average remaining contractual term		20 months
Preferred stock, shares issued (in shares)		0	0
Preferred stock, shares outstanding (in shares)		0	0
Preferred stock, shares authorized (in shares)		1,000,000	1,000,000
Preferred stock, par value (usd per share)		$ 0.01	$ 0.01
Number of shares of common stock purchased		726,347	1,756,831
Repurchased common stock value		$ 56,436	$ 121,191
Treasury stock, shares (in shares)		12,227,773	12,680,105
Shares issued in ESPP (USD per share)		$ 62.55
Shares issued in acquisition (in shares)		1,177,630
Accelerated Share Repurchase Agreement [Member]
Class of Stock [Line Items]
Stock Repurchased and Retired During Period, Shares			1,495,714
Accelerated Share Repurchases, Settlement (Payment) or Receipt			$ 100,000
Accelerated Share Repurchases, Final Price Paid Per Share			$ 66.86
Alpha
Class of Stock [Line Items]
Initial purchase consideration	$ 750,000
Payments to acquire businesses	650,000
Shares issued in acquisition, value	$ 93,268
Shares issued in acquisition (USD per share)	$ 84.92
Common Stock \| Alpha
Class of Stock [Line Items]
Shares issued in employee stock purchase plan (in shares)		3,256
Shares issued in acquisition (in shares)	1,177,630

Change in Number of Shares of Common Stock Outstanding (Detail) - shares	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares outstanding, beginning balance	41,915,000	43,447,536	43,189,502
Purchase of treasury stock	(726,347)	(1,756,831)
Shares issued in acquisition (in shares)	1,177,630
Shares issued as part of equity-based compensation plans, net of equity awards surrendered for option price and taxes	254,467	224,295	258,034
Shares outstanding, ending balance	42,620,750	41,915,000	43,447,536

Components of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ (41,717)	$ (152,824)	$ (97,349)
Before Reclassifications	(114,029)	112,279	(52,504)
Amount Reclassified from AOCI	13,064	(1,172)	(2,971)
Ending Balance	(142,682)	(41,717)	(152,824)
Pension funded status adjustment
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(22,503)	(25,555)	(21,861)
Before Reclassifications	339	1,692	(4,659)
Amount Reclassified from AOCI	1,373	1,360	965
Ending Balance	(20,791)	(22,503)	(25,555)
Net unrealized gain (loss) on derivative instruments
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(3,425)	1,975	388
Before Reclassifications	(8,396)	(2,868)	5,523
Amount Reclassified from AOCI	11,691	(2,532)	(3,936)
Ending Balance	(130)	(3,425)	1,975
Foreign currency translation adjustment
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(15,789)	(129,244)	(75,876)
Before Reclassifications	(105,972)	113,455	(53,368)
Amount Reclassified from AOCI	0	0	0
Ending Balance	$ (121,761)	$ (15,789)	$ (129,244)

Stockholders Equity and Noncontrolling Interests Reclassification from Accumulated Other Comprehensive Income (Details) - USD ($)	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Mar. 31, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Cost of goods sold									$ 2,104,612,000	$ 1,920,030,000	$ 1,713,115,000
Income tax expense		$ 13,483							21,584,000	118,493,000	54,472,000
Net earnings attributable to EnerSys stockholders	$ (18,538,000)	$ (48,417,000)	$ (47,424,000)	$ (45,860,000)	$ (54,018,000)	$ 25,847,000	$ (43,222,000)	$ (48,201,000)	(160,239,000)	(119,594,000)	(160,214,000)
Net unrealized gain (loss) on derivative instruments \| Reclassification out of Accumulated Other Comprehensive Income
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Cost of goods sold									15,281,000	(3,142,000)	(6,236,000)
Income tax expense									(3,590,000)	610,000	2,300,000
Net earnings attributable to EnerSys stockholders									11,691,000	(2,532,000)	(3,936,000)
Pension funded status adjustment \| Reclassification out of Accumulated Other Comprehensive Income
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Prior service costs and deferrals									1,704,000	1,771,000	1,431,000
Income tax expense									(331,000)	(411,000)	(466,000)
Net earnings attributable to EnerSys stockholders									$ 1,373,000	$ 1,360,000	$ 965,000

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Redeemable Noncontrolling Interests (Detail) $ in Thousands	12 Months Ended
Redeemable Noncontrolling Interests (Detail) $ in Thousands	Mar. 31, 2017 USD ($)
Temporary Equity, Number of Shares, Redemption Value and Other Disclosures [Abstract]
Redeemable noncontrolling interest, beginning balance	$ 5,997
Redeemable noncontrolling interests recognized in acquisitions of Powertech Batteries and Energy Leader Batteries India Limited	(2,021)
Deconsolidation of joint venture	(4,035)
Foreign currency translation adjustment	59
Redeemable noncontrolling interest, ending balance	$ 0

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants	3,750,392
Stock options granted	192,700	169,703	242,068
Stock-based compensation expense	$ 3,251	$ 700	$ 1,705
Stock-based compensation expense, net of tax	$ 634	$ 2,741	$ 457
Market price per unit of stock award	$ 75.32	$ 73.39	$ 65.88
Unrecognized compensation expense associated with non-vested incentive awards outstanding	$ 37,187
Nonvested stock, weighted average remaining contractual term	20 months
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market price per unit of stock award	$ 69.43
Stock unit grant during period	241,105
Restricted Shares Restricted Stock Units and Market Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 19,357	$ 16,712	$ 17,480
Stock unit grant during period	1,441	1,345	1,239
Equity-based compensation expense, tax benefit	$ 3,085	$ 3,325	$ 4,210
Non Employee Directors \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted	35,065	33,408	25,708
Market price per unit of stock award	$ 46.30	$ 46.24	$ 69.97
Management \| Nonqualified Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted	192,700
Vesting period, in years	3 years
Management \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market price per unit of stock award	$ 75.17	$ 83.14	$ 57.60
Stock unit grant during period	204,599	161,229	237,358
Management \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market price per unit of stock award	$ 68.48
Stock unit grant during period	45,883
Management \| Market Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market price per unit of stock award	$ 86.23	$ 105.74	$ 70.79
Stock unit grant during period	36,646	60,187	83,720
Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants	4,173,554
Stock Options Issued In Fiscal 2010 \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options expiration period (in years)	10 years

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Number of options
Number of Options outstanding, Beginning Balance	545,590	451,668	210,297
Number of Options, Granted	192,700	169,703	242,068
Number of Options, Exercised	(171,630)	(62,197)	(263)
Number of Options, Forfeited	(11,754)	(11,495)
Number of Options, Expired		2,089	434
Number of Options outstanding, Ending Balance	554,906	545,590	451,668	210,297
Number of Options, Exerciseable	186,823
Number of Options, Vested and Expected to Vest	545,299
Options outstanding, Weighted Average Remaining Contract Term
Options outstanding, Weighted Average Remaining Contract Term (Years)	8 years	8 years 4 months 24 days	8 years 4 months 24 days	8 years 6 months
Options exercisable, Weighted Average Remaining Contract Term (Years)	6 years 10 months 24 days
Options vested and expected to vest, Weighted Average Remaining Contract Term (Years)	8 years
Weighted average exercise price
Options outstanding, Weighted Average Exercise Price, Beginning Balance	$ 68.65	$ 62.29	$ 67.54
Weighted Average Exercise Price, Granted	75.17	83.14	57.60
Weighted Average Exercise Price, Exercised	63.66	63.44	18.25
Weighted Average Exercise Price, Expired	75.17	70.22
Weighted Average Exercise Price, Forfeited		18.25	18.25
Options outstanding, Weighted Average Exercise Price, Ending Balance	72.31	$ 68.65	$ 62.29	$ 67.54
Options exercisable, Weighted Average Exercise Price	69.34
Weighted Average Exercise Price, Vested and Expected to Vest	$ 72.24
Aggregate intrinsic value
Options outstanding, Aggregate Intrinsic Value, Beginning Balance	$ 2,679	$ 7,520	$ 218
Options exercised, aggregate intrinsic value	2,707	1,132	12
Options forfeited, aggregate intrinsic value	0	75
Options expired, aggregate intrinsic value		137	15
Options outstanding, Aggregate Intrinsic Value, Ending Balance	1,040	$ 2,679	$ 7,520	$ 218
Options exercisable, Aggregate Intrinsic Value	452
Options vested and expected to vest, aggregate intrinsic value	$ 1,038

Stock-Based Compensation - Summary of Information Regarding Stock Options Outstanding and Exercisable (Detail)	12 Months Ended
	Mar. 31, 2019 $ / shares shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Options \| shares	554,906
Weighted Average Remaining Contractual Life	8 years
Weighted Average Exercise Price \| $ / shares	$ 72.31

Stock Based Compensation Stock-Based Compensation - Summary of Assumptions Used for Market Share Units (Details) - $ / shares	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options	554,906
Weighted Average Remaining Contractual Life	8 years
Weighted Average Exercise Price	$ 72.31
Performance Market Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	2.66%	1.57%	0.94%
Dividend yield	0.00%	0.00%	0.00%
Time of maturity, in years	3 years	3 years	3 years
Expected volatility	26.41%	27.49%	31.74%
Market Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	2.77%	2.08%	1.41%
Dividend yield	0.93%	0.84%	1.22%
Time of maturity, in years	6 years	6 years	6 years
Expected volatility	26.80%	29.20%	30.40%
$55.00-$60.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options	137,599
Weighted Average Remaining Contractual Life	7 years 1 month 6 days
Weighted Average Exercise Price	$ 57.60
$65.01-$70.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options	73,368
Weighted Average Remaining Contractual Life	5 years 9 months 18 days
Weighted Average Exercise Price	$ 68.82
$75.01-$83.14
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options	343,939
Weighted Average Remaining Contractual Life	8 years 9 months 18 days
Weighted Average Exercise Price	$ 78.95

Stock-Based Compensation - Summary of Changes in Restricted Stock Units and Market Share Units (Detail) - $ / shares	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Granted	$ 75.32	$ 73.39	$ 65.88
Restricted Stock Units (RSUs)
Number of RSU and MSU
Number of RSU and MSU, Non-vested awards, Beginning Balance	633,751
Number of RSU and MSU, Granted	241,105
Number of RSU and MSU, Stock dividend	6,087
Number of RSU and MSU, Vested	(148,487)
Number of RSU and MSU, cancelled	(10,809)
Number of RSU and MSU, Non-vested awards, Ending Balance	721,647	633,751
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance	$ 56.60
Weighted Average Grant Date Fair Value, Granted	69.43
Weighted Average Grant Date Fair Value, Stock dividend	56.81
Weighted Average Grant Date Fair Value, Vested	68.55
Weighted Average Grant Date Fair Value, Canceled	72.56
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance	$ 57.72	$ 56.60
Market Share Unit Number (MSU)
Number of RSU and MSU
Number of RSU and MSU, Non-vested awards, Beginning Balance	349,941
Number of RSU and MSU, Granted	36,646
Number of RSU and MSU, Stock dividend	3,131
Number of RSU and MSU, Performance factor	143
Number of RSU and MSU, Vested	(3,482)
Number of RSU and MSU, cancelled	(33,795)
Number of RSU and MSU, Non-vested awards, Ending Balance	352,584	349,941
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance	$ 70.22
Weighted Average Grant Date Fair Value, Granted	85.84
Weighted Average Grant Date Fair Value, Stock dividend	72.60
Weighted Average Grant Date Fair Value, Performance factor	75.48
Weighted Average Grant Date Fair Value, Vested	59.94
Weighted Average Grant Date Fair Value, Canceled	62.21
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance	$ 72.83	$ 70.22
Performance condition-based Share Units (PSU)
Number of RSU and MSU
Number of RSU and MSU, Non-vested awards, Beginning Balance	0
Number of RSU and MSU, Granted	45,883
Number of RSU and MSU, Stock dividend	320
Number of RSU and MSU, Performance factor	0
Number of RSU and MSU, Vested	0
Number of RSU and MSU, cancelled	(3,677)
Number of RSU and MSU, Non-vested awards, Ending Balance	42,526	0
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance	$ 0
Weighted Average Grant Date Fair Value, Granted	68.48
Weighted Average Grant Date Fair Value, Stock dividend	68.48
Weighted Average Grant Date Fair Value, Performance factor	0
Weighted Average Grant Date Fair Value, Vested	0
Weighted Average Grant Date Fair Value, Canceled	68.48
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance	$ 68.48	$ 0

Earnings Per Share - Weighted Average Common Shares Basic and Common Shares Diluted (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Mar. 31, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net earnings attributable to EnerSys stockholders	$ 18,538	$ 48,417	$ 47,424	$ 45,860	$ 54,018	$ (25,847)	$ 43,222	$ 48,201	$ 160,239	$ 119,594	$ 160,214
Basic (in shares)									42,335,023	42,612,036	43,389,333
Dilutive effect of:
Common shares from exercise and lapse of equity awards, net of shares assumed reacquired (in shares)									673,929	507,820	623,210
Diluted weighted-average number of common shares outstanding (in shares)									43,008,952	43,119,856	44,012,543
Basic earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.43	$ 1.14	$ 1.13	$ 1.09	$ 1.29	$ (0.61)	$ 1.01	$ 1.11	$ 3.79	$ 2.81	$ 3.69
Diluted earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.42	$ 1.12	$ 1.11	$ 1.08	$ 1.27	$ (0.61)	$ 1.00	$ 1.09	$ 3.73	$ 2.77	$ 3.64
Anti-dilutive equity awards not included in diluted weighted-average common shares (in shares)									355,728,000	59,482,000	1,295,000

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Earnings Per Share - Additional Information (Detail) - Accelerated Share Repurchase Agreement [Member]	12 Months Ended
	Mar. 31, 2018 $ / shares shares
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Stock Repurchased and Retired During Period, Shares \| shares	1,495,714
Accelerated Share Repurchases, Final Price Paid Per Share \| $ / shares	$ 66.86

Commitments, Contingencies and Litigation - Additional Information (Detail) € in Thousands			1 Months Ended			3 Months Ended			12 Months Ended
	Jun. 11, 2013 USD ($)	Jun. 11, 2013 EUR (€)	Jul. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2018 EUR (€)	Mar. 31, 2019 USD ($) Employee	Mar. 31, 2018 USD ($)
Commitments, Contingencies And Litigation [Line Items]
Reserves for anti-competition investigations							$ 2,326,000		$ 7,258,000	$ 2,326,000
Reserves of environmental liabilities									$ 1,081,000	1,109,000
Company number of employees \| Employee									11,000
Percentage of employees covered by collective bargaining agreements									27.00%
Percentage of collective bargaining agreements that expire in next twelve months									10.00%
Average term of collective bargaining agreements									2 years
Longest term of collective bargaining agreements									3 years
Litigation Settlement, Amount Awarded from Other Party	$ 2,756,000	€ 2,000				$ 2,843
Belgium Anti-Competition Proceeding
Commitments, Contingencies And Litigation [Line Items]
Penalties paid relating to anti-competition investigations					$ 1,962,000
Legal proceedings charge									$ 2,402
Reserves for anti-competition investigations							2,326,000		0	2,326,000
Germany Anti-competition Proceedings
Commitments, Contingencies And Litigation [Line Items]
Penalties paid relating to anti-competition investigations				$ 14,811,000
Legal proceedings charge									7,258,000
Reserves for anti-competition investigations							0		$ 7,258,000	$ 0
Dutch Anti-Competition Proceedings [Member]
Commitments, Contingencies And Litigation [Line Items]
Penalties paid relating to anti-competition investigations			$ 11,229,000
Settled Litigation [Member]
Commitments, Contingencies And Litigation [Line Items]
Litigation Settlement, Amount Awarded from Other Party							$ 2,843,000	€ 2,500

Restructuring Plans and Other Exit Charges - Additional Information (Detail)	3 Months Ended									12 Months Ended				15 Months Ended	33 Months Ended
	Mar. 31, 2019 USD ($)	Dec. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jul. 01, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Oct. 01, 2017 USD ($)	Jul. 02, 2017 USD ($)	Jul. 03, 2016 USD ($)	Mar. 31, 2019 USD ($) Employee	Mar. 31, 2018 USD ($) Employee	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Jun. 30, 2016 USD ($) Employee	Dec. 31, 2017 USD ($) Employee
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges	$ 26,457,000	$ 5,392,000	$ 1,121,000	$ 1,739,000	$ 1,064,000	$ 1,808,000	$ 1,776,000	$ 833,000		$ 34,709,000	$ 5,481,000	$ 7,160,000
Write-off of assets relating to restructuring and other exit charges										26,308,000	3,736,000	1,435,000
Restructuring Related To Sale Of Geräte- und Akkumulatorenwerk Zwickau GmbH
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										4,930,000
Restructuring Charges Relating To Dissolving Joint Venture In Tunisia
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										$ 957,000
EMEA \| Restructurings Related to Improving Efficiency of Manufacturing, Sales, and Engineering Operations In EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											85,000	1,251,000	$ 5,232,000		$ 6,568,000
Expected reduction in number of employees \| Employee															130
Restructuring charges, cash charges related to employee severance and other charges											499,000	3,037,000	2,993,000
EMEA \| Restructurings Related to Improving Efficiency Related to Motive Power Production in EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											1,610,000	3,104,000
Expected reduction in number of employees \| Employee										45
Write-off of assets relating to restructuring and other exit charges										$ 4,714,000
Restructuring charges, cash charges related to employee severance and other charges										1,682,000	2,403,000	749,000
EMEA \| Restructurings Related to Improving Efficiency Related to Supply Chain and General Operations
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										3,104,000	$ 2,260,000
Expected reduction in number of employees \| Employee											85
Restructuring reserve	1,061,000									1,061,000
Write-off of assets relating to restructuring and other exit charges											$ 7,700,000
Restructuring charges, cash charges related to employee severance and other charges										2,844,000	1,350,000
Expected remaining restructuring charges	2,200,000									2,200,000
EMEA \| Restructurings Related To Improving Efficiencies Of Reserve Power Operations In EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										$ 347,000
Expected reduction in number of employees \| Employee										35
Restructuring reserve	262,000									$ 262,000
Write-off of assets relating to restructuring and other exit charges										2,500,000
Restructuring charges, cash charges related to employee severance and other charges										83,000
EMEA \| Employee Severance \| Restructurings Related to Improving Efficiency of Manufacturing, Sales, and Engineering Operations In EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges															$ 6,161,000
EMEA \| Other Charges \| Restructurings Related to Improving Efficiency of Manufacturing, Sales, and Engineering Operations In EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges															$ 407,000
EMEA \| Non Cash Charges \| Restructurings Related to Improving Efficiency Related to Supply Chain and General Operations
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											69,000
Asia \| Restructurings Related To Completing Transfer of Equipment and Clean-Up of Manufacturing Facility in Jiangdu
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											212,000	779,000
Write-off of assets relating to restructuring and other exit charges											991,000
Restructuring charges, cash charges related to employee severance and other charges											341,000	$ 648,000
Asia \| Restructuring Program To Improve Efficiencies Of Operations In Asia And Conversion Of India Operations
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										$ 2,772,000
Expected reduction in number of employees \| Employee										150
Restructuring reserve	1,139,000									$ 1,139,000
Write-off of assets relating to restructuring and other exit charges										4,500,000
Restructuring charges, cash charges related to employee severance and other charges										1,683,000
Asia \| Restructuring Related To Improving Profitability In India
Restructuring Cost and Reserve [Line Items]
Write-off of assets relating to restructuring and other exit charges										660,000
Asia \| Non Cash Charges \| Restructuring Program To Improve Efficiencies Of Operations In Asia And Conversion Of India Operations
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										771,000
Americas \| Restructuring Related to Improving the Efficiency of Manufacturing Operations in the Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges									$ 174,000				1,488,000	$ 2,379,000
Expected reduction in number of employees \| Employee														100
Restructuring charges, cash charges related to employee severance and other charges									924,000				119,000
Americas \| Restructurings Related to Improving Efficiencies of General Operations in the Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											$ 960,000
Expected reduction in number of employees \| Employee											60
Write-off of assets relating to restructuring and other exit charges											$ 960,000
Restructuring charges, cash charges related to employee severance and other charges										207,000	755,000
Americas \| Restructurings Related To Improving Efficiencies Of Operations In The Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										$ 1,970,000
Expected reduction in number of employees \| Employee										100
Restructuring reserve	490,000									$ 490,000
Write-off of assets relating to restructuring and other exit charges										4,600,000
Restructuring charges, cash charges related to employee severance and other charges										1,480,000
Americas \| Employee Severance \| Restructuring Related to Improving the Efficiency of Manufacturing Operations in the Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges														$ 1,043,000
Americas \| Pension Curtailment \| Restructuring Related to Improving the Efficiency of Manufacturing Operations in the Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges													313,000	313,000
Americas \| Non Cash Charges \| Restructuring Related to Improving the Efficiency of Manufacturing Operations in the Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges									$ 718,000				$ 305,000	$ 1,023,000
Americas \| Non Cash Charges \| Restructurings Related To Improving Efficiencies Of Operations In The Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										2,095,000
Americas \| Facility Closing
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges							75,000
Gain (Loss) on Sale of Properties							$ (210,000)
Americas \| Inventory Write-Off \| Restructurings Related to Improving Efficiencies of General Operations in the Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											3,457,000
Closure Of Facility In Targovishte, Bulgaria
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										17,652,000
Expected cost remaining	$ 30,000,000									30,000,000
Closure Of Facility In Targovishte, Bulgaria \| Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										2,694,000
Closure Of Facility In Targovishte, Bulgaria \| Inventory Write-Off
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										2,590,000
Closure Of Facility In Targovishte, Bulgaria \| Fixed Asset Write Offs
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										14,958,000
South Africa Joint Venture Business Exit
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											3,292,000
South Africa Joint Venture Business Exit \| Employee Severance
Restructuring Cost and Reserve [Line Items]
Write-off of assets relating to restructuring and other exit charges											717,000
Restructuring charges, cash charges related to employee severance and other charges											2,575,000
South Africa Joint Venture Business Exit \| Inventory Write-Off
Restructuring Cost and Reserve [Line Items]
Write-off of assets relating to restructuring and other exit charges											2,157,000
South Africa Joint Venture Business Exit \| Change in Estimate of Contract losses
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											1,099,000
South Africa Joint Venture Business Exit \| Deconsolidation of Joint Venture
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											$ (341,000)
Cost of Sales \| Asia \| Non Cash Charges \| Restructuring Related To Improving Profitability In India
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										$ 526,000

Restructuring Plans and Other Exit Charges - Acquisition and Non-Acquisition Related Restructuring Reserve (Details) - Non-Acquisition Related Restructuring Plans - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Restructuring Reserve [Roll Forward]
Beginning balance	$ 2,909	$ 2,812	$ 2,989
Accrued	8,193	5,202	5,308
Costs incurred	(7,979)	(5,423)	(5,358)
Foreign currency impact and other	(171)	318	(127)
Ending balance	2,952	2,909	2,812
Employee Severance
Restructuring Reserve [Roll Forward]
Beginning balance	2,893	2,668	2,964
Accrued	6,554	4,757	4,566
Costs incurred	(6,893)	(4,849)	(4,754)
Foreign currency impact and other	(198)	317	(108)
Ending balance	2,356	2,893	2,668
Other
Restructuring Reserve [Roll Forward]
Beginning balance	16	144	25
Accrued	1,639	445	742
Costs incurred	(1,086)	(574)	(604)
Foreign currency impact and other	27	1	(19)
Ending balance	$ 596	$ 16	$ 144

Warranty (Detail) - USD ($) $ in Thousands	12 Months Ended
Warranty (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Product Warranty Accrual [Roll Forward]
Balance at beginning of year	$ 50,602	$ 46,116	$ 48,422
Current year provisions	23,679	21,706	17,852
Costs incurred	(25,053)	(18,820)	(15,945)
Warranty reserves of acquired business - Alpha	7,535	0	0
Foreign currency translation adjustment	(2,195)	1,600	(4,213)
Balance at end of year	$ 54,568	$ 50,602	$ 46,116

Other (Income) Expense, Net (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Other Income and Expenses [Abstract]
Foreign exchange transaction (gains) losses	$ (3,044)	$ 5,499	$ (662)
Non-service components of pension expense	1,502	1,464	1,252
Other	928	556	1,631
Total	$ (614)	$ 7,519	$ 2,221

Business Segments - Schedule of Summarized Financial Information by Reportable Segments Segments (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Mar. 31, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Net sales	$ 796,603	$ 680,022	$ 660,462	$ 670,930	$ 683,042	$ 658,935	$ 617,289	$ 622,625	$ 2,808,017	$ 2,581,891	$ 2,367,149
Intersegment sales									186,558	186,052	141,773
Total operating earnings	34,978	49,951	63,357	64,179	67,725	68,785	64,364	69,972	212,465	270,846	237,113
Inventory adjustment relating to exit activities - EMEA	(3,516)	(3,747)			(3,457)				(10,379)	(3,457)	(2,157)
Restructuring charges	(26,457)	$ (5,392)	$ (1,121)	$ (1,739)	(1,064)	$ (1,808)	$ (1,776)	$ (833)	(34,709)	(5,481)	(7,160)
Impairment of goodwill, indefinite-lived intangibles and fixed assets - See Note 5									0	0	(12,216)
Gain on sale of facility - Asia									258	(116)	7
Property, plant, and equipment, net	409,439				390,260				409,439	390,260	348,549
Capital Expenditures									70,372	69,832	50,072
Depreciation and amortization									63,348	54,317	53,945
Reserve Power
Segment Reporting Information [Line Items]
Net sales									1,416,173	1,247,900	1,142,327
Motive Power
Segment Reporting Information [Line Items]
Net sales									1,391,844	1,333,991	1,224,822
Americas
Segment Reporting Information [Line Items]
Net sales									1,690,912	1,429,888	1,332,353
Intersegment sales									28,753	29,513	26,039
Total operating earnings									186,814	189,466	191,801
Inventory step up to fair value relating to acquisition - Americas									(7,263)	0	0
Inventory adjustment relating to exit activities - EMEA									0	(3,457)	0
Restructuring charges									(4,066)	(1,246)	(892)
Impairment of goodwill, indefinite-lived intangibles and fixed assets - See Note 5									0	0	(9,346)
Property, plant, and equipment, net	257,559				210,998				257,559	210,998	190,169
Capital Expenditures									45,029	46,905	34,809
Depreciation and amortization									40,675	30,421	30,204
Europe
Segment Reporting Information [Line Items]
Inventory adjustment relating to exit activities - EMEA									(2,590)	0	(2,157)
Legal proceedings charge									(4,437)	0	(23,725)
EMEA
Segment Reporting Information [Line Items]
Net sales									860,563	849,420	763,013
Intersegment sales									123,274	133,164	93,150
Total operating earnings									71,963	77,671	77,376
Restructuring charges									(26,989)	(4,023)	(5,487)
Impairment of goodwill, indefinite-lived intangibles and fixed assets - See Note 5									0	0	(4,670)
Property, plant, and equipment, net	94,932				118,263				94,932	118,263	100,042
Capital Expenditures									18,972	18,392	13,733
Depreciation and amortization									15,128	16,198	15,693
Asia
Segment Reporting Information [Line Items]
Net sales									256,542	302,583	271,783
Intersegment sales									34,531	23,375	22,584
Total operating earnings									3,213	12,647	14,994
Inventory adjustment relating to exit activities - EMEA									(526)	0	0
Restructuring charges									(3,654)	(212)	(781)
Property, plant, and equipment, net	$ 56,948				$ 60,999				56,948	60,999	58,338
Capital Expenditures									6,371	4,535	1,530
Depreciation and amortization									$ 7,545	$ 7,698	$ 8,048

Business Segments - Additional Information (Detail) $ in Thousands	12 Months Ended
	Mar. 31, 2019 USD ($) Country	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Operations in number of countries \| Country	100
Property, plant, and equipment, net	$ 409,439	$ 390,260	$ 348,549
United States
Segment Reporting Information [Line Items]
Percentage of sales to customers	48.50%	49.20%	50.00%
Property, plant, and equipment, net	$ 202,985	$ 176,144

Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Mar. 31, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 796,603	$ 680,022	$ 660,462	$ 670,930	$ 683,042	$ 658,935	$ 617,289	$ 622,625	$ 2,808,017	$ 2,581,891	$ 2,367,149
Gross profit	202,266	164,546	160,880	165,334	167,388	167,310	160,248	163,458	693,026	658,404	651,877
Operating earnings	34,978	49,951	63,357	64,179	67,725	68,785	64,364	69,972	212,465	270,846	237,113
Net earnings	18,546	48,614	47,447	46,020	54,139	(25,779)	43,151	48,322	160,627	119,833	158,223
Net earnings attributable to EnerSys stockholders	$ 18,538	$ 48,417	$ 47,424	$ 45,860	$ 54,018	$ (25,847)	$ 43,222	$ 48,201	$ 160,239	$ 119,594	$ 160,214
Basic earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.43	$ 1.14	$ 1.13	$ 1.09	$ 1.29	$ (0.61)	$ 1.01	$ 1.11	$ 3.79	$ 2.81	$ 3.69
Diluted earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.42	$ 1.12	$ 1.11	$ 1.08	$ 1.27	$ (0.61)	$ 1.00	$ 1.09	$ 3.73	$ 2.77	$ 3.64

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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Quarterly Financial Data (Additional Information) (Detail) € in Thousands			3 Months Ended								12 Months Ended
	Jun. 11, 2013 USD ($)	Jun. 11, 2013 EUR (€)	Mar. 31, 2019 USD ($)	Dec. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jul. 01, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Oct. 01, 2017 USD ($)	Jul. 02, 2017 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)
Quarterly Financial Information Disclosure [Abstract]
Inventory Adjustments			$ 2,590			$ 526
Inventory step up to fair value relating to Alpha acquisition and exit activities			3,516,000	$ 3,747,000			$ 3,457,000				$ 10,379,000	$ 3,457,000	$ 2,157,000
Restructuring and other exit charges			26,457,000	5,392,000	$ 1,121,000	$ 1,739,000	1,064,000	$ 1,808,000	$ 1,776,000	$ 833,000	34,709,000	5,481,000	7,160,000
Litigation Settlement, Amount Awarded from Other Party	$ 2,756,000	€ 2,000		2,843
Litigation Settlement, Expense			$ 7,280								4,437,000	0	23,725,000
Income tax expense				$ 13,483							21,584,000	118,493,000	54,472,000
Impairment of goodwill											0	0	12,216,000
Gain on sale of facility - Asia											258,000	(116,000)	7,000
Tax expense relating to Tax Cuts and Jobs Act of 2017							$ 4,106,000	$ 77,347,000			$ (13,483,000)	$ 83,400,000	$ 0

Subsequent Events - Additional Information (Detail)	May 16, 2019 $ / shares
Subsequent Event \| Dividend Declared
Subsequent Event [Line Items]
Common Stock cash dividends, per share	$ 0.175

Valuation and Qualifying Accounts Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Deferred tax asset—valuation allowance
Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 15,255	$ 27,053	$ 25,416
Additions Charged to Expense	2,978	4,853	4,305
Charge-Offs	(99)	(14,132)	(2,255)
Business Combination Adjustments	1,157	0	0
Other	(1,772)	(2,519)	(413)
Balance at End of Period	17,519	15,255	27,053
Allowance for doubtful accounts
Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	12,643	12,662	11,393
Additions Charged to Expense	1,385	822	1,794
Charge-Offs	(2,459)	(1,400)	(173)
Other	(756)	559	(352)
Balance at End of Period	$ 10,813	$ 12,643	$ 12,662

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Mar. 31, 2019	May 24, 2019	Sep. 30, 2018
Document and Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Trading Symbol	ENS
Entity Registrant Name	ENERSYS
Entity Central Index Key	0001289308
Current Fiscal Year End Date	--03-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		42,856,811
Entity Public Float			$ 3,657,002,760

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Current assets:
Cash and cash equivalents	$ 299,212	$ 522,118
Accounts receivable, net of allowance for doubtful accounts (2019–$10,813; 2018–$12,643)	624,136	546,325
Inventories	503,869	414,234
Prepaid and other current assets	109,431	56,910
Total current assets	1,536,648	1,539,587
Property, plant, and equipment, net	409,439	390,260
Goodwill	656,399	352,805
Other intangible assets, net	462,316	147,141
Deferred taxes	40,466	44,402
Other assets	12,925	12,730
Total assets	3,118,193	2,486,925
Current liabilities:
Short-term debt	54,490	18,341
Current portion of capital lease obligations	10,113	89
Accounts payable	292,449	258,982
Accrued expenses	255,881	214,118
Total current liabilities	612,933	491,530
Long-term debt, net of unamortized debt issuance costs	971,756	579,535
Capital lease obligations	175	55
Deferred taxes	82,112	33,607
Other liabilities	165,200	181,087
Total liabilities	1,832,176	1,285,814
Commitments and contingencies
Equity:
Preferred Stock, $0.01 par value, 1,000,000 shares authorized, no shares issued or outstanding at March 31, 2019 and at March 31, 2018	0	0
Common Stock, $0.01 par value per share, 135,000,000 shares authorized, 54,848,523 shares issued and 42,620,750 shares outstanding at March 31, 2019; 54,595,105 shares issued and 41,915,000 shares outstanding at March 31, 2018	548	546
Additional paid-in capital	512,696	477,288
Treasury stock at cost, 12,227,773 shares held as of March 31, 2019 and 12,680,105 shares held as of March 31, 2018	(530,760)	(560,991)
Retained earnings	1,450,325	1,320,549
Accumulated other comprehensive loss	(142,682)	(41,717)
Contra equity - indemnification receivable	(7,840)	0
Total EnerSys stockholders’ equity	1,282,287	1,195,675
Nonredeemable noncontrolling interests	3,730	5,436
Total equity	1,286,017	1,201,111
Total liabilities and equity	$ 3,118,193	$ 2,486,925

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 10,813	$ 12,643
Preferred stock, par value (usd per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	135,000,000	135,000,000
Common stock, shares issued (in shares)	54,848,523	54,595,105
Common stock, shares outstanding (in shares)	42,620,750	41,915,000
Treasury stock, shares (in shares)	12,227,773	12,680,105

Consolidated Statements of Income - USD ($)	12 Months Ended
Consolidated Statements of Income - USD ($)	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Net sales	$ 2,808,017,000	$ 2,581,891,000	$ 2,367,149,000
Cost of goods sold	2,104,612,000	1,920,030,000	1,713,115,000
Inventory step up to fair value relating to Alpha acquisition and exit activities	10,379,000	3,457,000	2,157,000
Gross profit	693,026,000	658,404,000	651,877,000
Operating expenses	441,415,000	382,077,000	369,863,000
Restructuring and other exit charges	34,709,000	5,481,000	7,160,000
Impairment of goodwill	0	0	12,216,000
Impairment of indefinite-lived intangibles and fixed assets	0	0	1,800,000
Legal proceedings charge, net	(4,437,000)	0	(23,725,000)
Operating earnings	212,465,000	270,846,000	237,113,000
Interest expense	30,868,000	25,001,000	22,197,000
Other (income) expense, net	(614,000)	7,519,000	2,221,000
Earnings before income taxes	182,211,000	238,326,000	212,695,000
Income tax expense	21,584,000	118,493,000	54,472,000
Net earnings	160,627,000	119,833,000	158,223,000
Net earnings (losses) attributable to noncontrolling interests	388,000	239,000	(1,991,000)
Net earnings attributable to EnerSys stockholders	$ 160,239,000	$ 119,594,000	$ 160,214,000
Net earnings per common share attributable to EnerSys stockholders:
Basic (usd per share)	$ 3.79	$ 2.81	$ 3.69
Diluted (usd per share)	3.73	2.77	3.64
Dividends per common share (usd per share)	$ 0.70	$ 0.70	$ 0.70
Weighted-average number of common shares outstanding:
Basic (in shares)	42,335,023	42,612,036	43,389,333
Diluted (in shares)	43,008,952	43,119,856	44,012,543

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net earnings	$ 160,627	$ 119,833	$ 158,223
Other comprehensive income (loss):
Net unrealized gain (loss) on derivative instruments, net of tax	3,295	(5,400)	1,587
Pension funded status adjustment, net of tax	1,712	3,052	(3,694)
Foreign currency translation adjustment	(106,555)	113,739	(53,730)
Total other comprehensive (loss) income, net of tax	(101,548)	111,391	(55,837)
Total comprehensive income	59,079	231,224	102,386
Comprehensive (income) loss attributable to noncontrolling interests	(195)	523	(2,353)
Comprehensive income attributable to EnerSys stockholders	$ 59,274	$ 230,701	$ 104,739

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Contra-Equity	Total EnerSys Stockholders’ Equity	Non- redeemable Non- Controlling Interests
Beginning Balance at Mar. 31, 2016	$ 1,018,435	$ 0	$ 541	$ 452,097	$ (439,800)	$ 1,097,642	$ (97,349)	$ 0	$ 1,013,131	$ 5,304
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	19,185			19,185					19,185
Shares issued under equity awards (taxes paid related to net share settlement of equity awards), net	(7,444)		3	(7,447)					(7,444)
Other	(480)			(480)					(480)
Net earnings (excluding losses attributable to redeemable noncontrolling interests)	160,244					160,214			160,214	30
Dividends ($0.70 per common share)	(30,400)			737		(31,137)			(30,400)
Redemption value adjustment attributable to redeemable noncontrolling interests	4,725					4,725			4,725
Other comprehensive income:
Pension funded status adjustment, (net of tax (expense) benefit)	(3,694)						(3,694)		(3,694)
Net unrealized gain (loss) on derivative instruments (net of tax (benefit) expense)	1,587						1,587		1,587
Foreign currency translation adjustment (excludes losses related to redeemable noncontrolling interests)	(53,789)						(53,368)		(53,368)	(421)
Ending Balance at Mar. 31, 2017	1,108,369	0	544	464,092	(439,800)	1,231,444	(152,824)	0	1,103,456	4,913
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	19,453			19,453					19,453	0
Shares issued under equity awards (taxes paid related to net share settlement of equity awards), net	(6,531)		2	(6,533)					(6,531)
Other	(539)			(402)		(137)			(539)
Purchase of common stock	(121,191)				(121,191)				(121,191)
Net earnings (excluding losses attributable to redeemable noncontrolling interests)	119,833					119,594			119,594	239
Dividends ($0.70 per common share)	(29,674)			678		(30,352)			(29,674)
Other comprehensive income:
Pension funded status adjustment, (net of tax (expense) benefit)	3,052						3,052		3,052
Net unrealized gain (loss) on derivative instruments (net of tax (benefit) expense)	(5,400)						(5,400)		(5,400)
Foreign currency translation adjustment (excludes losses related to redeemable noncontrolling interests)	113,739						113,455		113,455	284
Ending Balance at Mar. 31, 2018	1,201,111	0	546	477,288	(560,991)	1,320,549	(41,717)	0	1,195,675	5,436
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	22,608			22,608					22,608
Exercise of stock options	9,048		2	9,046					9,048
Shares issued under equity awards (taxes paid related to net share settlement of equity awards), net	(3,630)			(3,630)					(3,630)
Other	(141)			(141)					(141)
Purchase of common stock	(56,436)				(56,436)				(56,436)
Reissuance of treasury stock, on LIFO basis, towards Alpha purchase consideration	93,268			6,805	86,463				93,268
Reissuance of treasury stock towards employee stock purchase plan	204				204				204
Contra equity - indemnification receivable for acquisition related tax liability	(7,840)							(7,840)	(7,840)	0
Net earnings (excluding losses attributable to redeemable noncontrolling interests)	160,627					160,239			160,239	388
Dividends ($0.70 per common share)	(29,743)			720		(30,463)			(29,743)
Noncontrolling Interest In Net Income (Loss) Joint Venture Partners, Dissolution	(1,511)									(1,511)
Other comprehensive income:
Pension funded status adjustment, (net of tax (expense) benefit)	1,712						1,712		1,712
Net unrealized gain (loss) on derivative instruments (net of tax (benefit) expense)	3,295						3,295		3,295
Foreign currency translation adjustment (excludes losses related to redeemable noncontrolling interests)	(106,555)						(105,972)		(105,972)	(583)
Ending Balance at Mar. 31, 2019	$ 1,286,017	$ 0	$ 548	$ 512,696	$ (530,760)	$ 1,450,325	$ (142,682)	$ (7,840)	$ 1,282,287	$ 3,730

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Statement of Stockholders' Equity [Abstract]
Losses attributable to redeemable noncontrolling interests		$ (2,021)	$ (4,272)
Dividends per common share	$ 0.70	$ 0.70	$ 0.7
Pension funded status adjustment, tax benefit (expense)	$ 808	$ (142)	$ (587)
Net unrealized gain (loss) on derivative instruments, tax (benefit) expense	$ (2,071)	929	277
Foreign currency translation adjustment, related to redeemable noncontrolling interests		$ 59	$ 1,068

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities
Net earnings	$ 160,627	$ 119,833	$ 158,223
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	63,348	54,317	53,945
Write-off of assets relating to restructuring and other exit charges	26,308	3,736	1,435
Non-cash write-off of property, plant and equipment	0	0	6,300
Impairment of goodwill	0	0	12,216
Impairment of indefinite-lived intangibles and fixed assets	0	0	1,800
Derivatives not designated in hedging relationships:
Net losses (gains)	1,856	(180)	471
Cash (settlements) proceeds	(1,802)	43	(1,225)
Provision for doubtful accounts	1,385	822	1,794
Deferred income taxes	(6,456)	(20,313)	1,455
Non-cash interest expense	1,316	1,603	1,388
Stock-based compensation	22,608	19,453	19,185
(Gain) loss on disposal of property, plant, and equipment	(258)	116	(7)
Changes in assets and liabilities, net of effects of acquisitions:
Accounts receivable	5,974	(32,242)	(13,535)
Inventories	(46,614)	(38,075)	(42,792)
Prepaid and other current assets	(20,195)	14,470	3,721
Other assets	(7,611)	(1,150)	2,034
Accounts payable	9,944	21,266	845
Legal proceedings accrual	7,258	0	23,725
Accrued expenses	(4,937)	(26,614)	9,333
Other liabilities	(14,896)	93,963	5,719
Net cash provided by operating activities	197,855	211,048	246,030
Cash flows from investing activities
Capital expenditures	(70,372)	(69,832)	(50,072)
Purchase of businesses	(654,614)	(2,988)	(12,392)
Proceeds from disposal of property, plant, and equipment	1,103	463	631
Net cash used in investing activities	(723,883)	(72,357)	(61,833)
Cash flows from financing activities
Net borrowings (repayments) on short-term debt	37,424	214	(4,600)
Debt issuance costs	(1,393)	(2,677)	0
Capital lease obligations and other	368	(29)	(98)
Option proceeds	9,048	958	3
Payment of taxes related to net share settlement of equity awards	(3,630)	(7,489)	(7,447)
Purchase of treasury stock	(56,436)	(121,191)	0
Dividends paid to stockholders	(29,743)	(29,674)	(30,400)
Net cash provided by (used in) financing activities	346,577	(166,888)	(62,542)
Effect of exchange rate changes on cash and cash equivalents	(43,455)	49,986	(18,633)
Net (decrease) increase in cash and cash equivalents	(222,906)	21,789	103,022
Cash and cash equivalents at beginning of year	522,118	500,329	397,307
Cash and cash equivalents at end of year	299,212	522,118	500,329
Non-cash investing and financing activities:
Common stock issued as partial consideration for Alpha acquisition	93,268	0	0
2017 Revolver borrowings
Cash flows from financing activities
Proceeds from Revolver borrowings	531,100	379,750	0
Repayments of Revolver borrowings	(427,600)	(244,250)	0
2011 Revolver borrowings
Cash flows from financing activities
Proceeds from Revolver borrowings	0	147,050	262,000
Repayments of Revolver borrowings	0	(312,050)	(267,000)
Amended 2017 Term Loan
Cash flows from financing activities
Repayments of Revolver borrowings	(11,666)	0	0
Proceeds from Amended 2017 Term Loan	299,105	150,000	0
2011 Term Loan
Cash flows from financing activities
Repayments of 2011 Term Loan	$ 0	$ (127,500)	$ (15,000)

Summary of Significant Accounting Policies

12 Months Ended

Mar. 31, 2019

Summary of Significant Accounting Policies

Description of Business

Principles of Consolidation

Foreign Currency Translation

Revenue Recognition

ASC 606, Revenue from Contracts with Customers, was adopted for the fiscal year beginning April 1, 2018.

Concurrent with the adoption of the new standard, the Company has updated its revenue recognition policy as follows:

The Company determines revenue recognition by applying the following steps:

1. identify the contract with a customer;

2. identify the performance obligations in the contract;

3. determine the transaction price;

4. allocate the transaction price to the performance obligations; and

5. recognize revenue as the performance obligations are satisfied.

The Company's primary performance obligation to its customers is the delivery of finished goods and products, pursuant to

purchase orders. Control of the products sold typically transfers to its customers at the point in time when the goods are shipped

as this is also when title generally passes to its customers under the terms and conditions of our customer arrangements.

The Company's typical payment terms are 30 days and sales arrangements do not contain any significant financing component for its customers.

The Company applies a policy election to exclude transaction taxes collected from customers from sales when the tax is both imposed on and concurrent with a specific revenue-producing transaction.

Warranties

Cash and Cash Equivalents

Cash and cash equivalents include all highly liquid investments with an original maturity of three months or less when purchased.

Concentration of Credit Risk

Accounts Receivable

Inventories

Inventories are stated at the lower of cost or market. Cost is determined using the first-in, first-out (FIFO) method. The cost of inventory consists of material, labor, and associated overhead.

Property, Plant, and Equipment

Maintenance and repairs are expensed as incurred. Interest on capital projects is capitalized during the construction period.

Business Combinations

intangible assets is recorded to goodwill. The results of operations of the acquired business are included in the Company’s operating results from the date of acquisition.

Goodwill and Other Intangible Assets

Impairment of Long-Lived Assets

Environmental Expenditures

Derivative Financial Instruments

The Company does not have any credit-related contingent features associated with its derivative instruments.

Fair Value of Financial Instruments

The Company groups its recurring, non-recurring and disclosure-only fair value measurements into the following levels when making fair value measurement disclosures:



Level 1		Inputs are unadjusted quoted prices in active markets for identical assets or liabilities.

Level 2		Inputs are quoted prices for similar assets or liabilities in an active market, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable and market-corroborated inputs which are derived principally from or corroborated by observable market data.

Level 3		Inputs are derived from valuation techniques in which one or more significant inputs or value drivers are unobservable.

Income Taxes

The Company recognizes tax related interest and penalties in income tax expense in its Consolidated Statement of Income.

Deferred Financing Fees

Stock-Based Compensation Plans

Market and Performance condition-based awards

The Company grants market condition-based awards and performance condition-based awards.

Restricted Stock Units

Stock Options

Forfeitures

Forfeitures of share-based awards are estimated at the time of grant and revised, if necessary, in subsequent periods if actual

forfeitures differ from those estimates.

Earnings Per Share

Segment Reporting


•	Americas, which includes North and South America, with segment headquarters in Reading, Pennsylvania, U.S.A.,


•	EMEA, which includes Europe, the Middle East and Africa, with segment headquarters in Zug, Switzerland, and


•	Asia, which includes Asia, Australia and Oceania, with segment headquarters in Singapore.

Recently Adopted Accounting Pronouncements

Accounting Pronouncements Issued But Not Adopted as of March 31, 2019


•	to adopt the optional transition method defined within ASU 2018-11 and not restate comparative prior periods but instead recognize a cumulative effect adjustment to the opening balance of retained earnings in the period of adoption;


•	to elect the package of three practical expedients addressing whether a contract contains a lease, lease classification and initial direct costs;

to combine lease and non-lease components as a single component for all asset classes;


•	to use a portfolio approach to determine the incremental borrowing rate; and


•	to apply the short-term lease exception to leases that, at the commencement date, has a lease term of 12 months or less and does not include an option to purchase the underlying asset that the lessee is reasonably certain to exercise.

Use of Estimates

Acquisitions

12 Months Ended

Mar. 31, 2019

Acquisitions

The acquired assets and assumed liabilities include the following:



Accounts receivable	$	115,467
Inventories	84,297
Other current assets	6,822
Other intangible assets	332,000
Property, plant and equipment	20,987
Other assets	9,005
Total assets acquired	$	568,578
Accounts payable	35,803
Accrued liabilities	41,918
Deferred income taxes	56,331
Other liabilities	12,642
Total liabilities assumed	$	146,694
Net assets acquired	$	421,884

Purchase price:
Cash paid for net assets acquired	$	650,000
Fair value of shares issued for net assets acquired	93,268
Working capital adjustment	(766		)
Total purchase consideration	742,502
Less: Fair value of acquired identifiable assets and liabilities	421,884
Goodwill	$	320,618

The following table summarizes the estimated fair value of Alpha's identifiable intangible assets and the initial assessment of their respective estimated lives:



	Type	Life in Years	Fair Value
Trademarks	Indefinite-lived	Indefinite	$	56,000
Customer relationships	Finite-lived	14	221,000
Technology	Finite-lived	10	55,000
Total identifiable intangible assets			$	332,000

The following unaudited summary information is presented on a consolidated pro forma basis as if the acquisition had occurred on April 1, 2017:



	Fiscal year ended
	March 31, 2019		March 31, 2018
Net sales	$	3,278,646	$	3,124,527
Net earnings attributable to EnerSys stockholders	207,904		126,965
Net earnings per share attributable to EnerSys stockholders - basic	4.79		2.90
Net earnings per share attributable to EnerSys stockholders - assuming dilution	4.71		2.87

The Company made no significant acquisitions in fiscal 2018 and 2017.

Inventories

12 Months Ended

Mar. 31, 2019



	March 31,
	2019		2018
Raw materials	$	138,718	$	92,216
Work-in-process	129,736		136,068
Finished goods	235,415		185,950
Total	$	503,869	$	414,234

Property, Plant, and Equipment

12 Months Ended

Mar. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Property, plant, and equipment consist of:



	March 31,
	2019			2018
Land, buildings, and improvements	$	268,006		$	273,506
Machinery and equipment	683,955			657,262
Construction in progress	54,278			49,900
	1,006,239			980,668
Less accumulated depreciation	(596,800		)	(590,408		)
Total	$	409,439		$	390,260

Goodwill and Other Intangible Assets

12 Months Ended

Mar. 31, 2019

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Other Intangible Assets

Information regarding the Company’s other intangible assets are as follows:



	March 31,
	2019							2018
	Gross Amount		Accumulated Amortization			Net Amount		Gross Amount		Accumulated Amortization			Net Amount
Indefinite-lived intangible assets:
Trademarks	$	152,484	$	(953	)	$	151,531	$	97,444	$	(953	)	$	96,491
Finite-lived intangible assets:
Customer relationships	286,664		(42,704		)	243,960		66,973		(31,500		)	35,473
Non-compete	3,025		(2,807		)	218		2,852		(2,759		)	93
Technology	77,779		(12,229		)	65,550		22,769		(8,872		)	13,897
Trademarks	2,003		(1,236		)	767		2,003		(1,151		)	852
Licenses	1,477		(1,187		)	290		1,491		(1,156		)	335
Total	$	523,432	$	(61,116	)	$	462,316	$	193,532	$	(46,391	)	$	147,141

Goodwill

The changes in the carrying amount of goodwill by reportable segment are as follows:



	Fiscal year ended March 31, 2019
	Americas			EMEA			Asia			Total
Balance at beginning of year	$	151,255		$	155,825		$	45,725		$	352,805
Acquisitions during the year	320,618			—			—			320,618
Foreign currency translation adjustment	(1,679		)	(12,556		)	(2,789		)	(17,024		)
Balance at end of year	$	470,194		$	143,269		$	42,936		$	656,399



	Fiscal year ended March 31, 2018
	Americas		EMEA		Asia		Total
Balance at beginning of year	$	146,982	$	138,813	$	42,862	$	328,657
Acquisitions during the year	3,670		—		—		3,670
Foreign currency translation adjustment	603		17,012		2,863		20,478
Balance at end of year	$	151,255	$	155,825	$	45,725	$	352,805

A reconciliation of goodwill and accumulated goodwill impairment losses, by reportable segment, is as follows:



	March 31, 2019
	Americas			EMEA			Asia			Total
Gross carrying value	$	528,039		$	149,422		$	48,115		$	725,576
Accumulated goodwill impairment charges	(57,845		)	(6,153		)	(5,179		)	(69,177		)
Net book value	$	470,194		$	143,269		$	42,936		$	656,399



	March 31, 2018
	Americas			EMEA			Asia			Total
Gross carrying value	$	209,100		$	161,978		$	50,904		$	421,982
Accumulated goodwill impairment charges	(57,845		)	(6,153		)	(5,179		)	(69,177		)
Net book value	$	151,255		$	155,825		$	45,725		$	352,805

Impairment of goodwill and indefinite-lived intangibles

The Company did not record any impairment relating to its goodwill and intangible assets during fiscal 2019 and 2018.

The Company estimated tax-deductible goodwill to be approximately $58,699 and $18,147 as of March 31, 2019 and 2018, respectively.

Prepaid and Other Current Assets

12 Months Ended

Mar. 31, 2019

Prepaid and Other Current Assets

Prepaid and other current assets consist of the following:



	March 31,
	2019		2018
Contract assets	$	38,778	$	—
Prepaid non-income taxes	22,490		22,583
Non-trade receivables	10,823		4,087
Prepaid income taxes	9,608		8,921
Other	27,732		21,319
Total	$	109,431	$	56,910

Accrued Expenses

12 Months Ended

Mar. 31, 2019

Accrued Expenses

Accrued expenses consist of the following:



	March 31,
	2019		2018
Payroll and benefits	$	54,285	$	50,053
Accrued selling expenses	35,394		34,831
Warranty	21,646		22,637
VAT and other non-income taxes	17,125		13,155
Project related accruals	16,301		—
Contract liabilities	15,162		—
Freight	14,423		15,810
Income taxes payable	9,234		19,696
Legal proceedings	7,258		2,326
Interest	7,248		6,762
Tax Act - Transition Tax	5,290		7,800
Restructuring	2,952		2,909
Pension	1,207		1,657
Deferred income	—		9,387
Other	48,356		27,095
Total	$	255,881	$	214,118

Debt

12 Months Ended

Mar. 31, 2019

Debt

The following summarizes the Company’s long-term debt:



	As of March 31,
	2019				2018
	Principal		Unamortized Issuance Costs		Principal		Unamortized Issuance Costs
5.00% Senior Notes, due 2023	$	300,000	$	2,497	$	300,000	$	3,122
Amended Credit Facility, due 2022^*	677,315		3,062		285,500		2,843
	$	977,315	$	5,559	$	585,500	$	5,965
Less: Unamortized issuance costs	5,559				5,965
Less: Current portion	—				—
Long-term debt, net of unamortized issuance costs	$	971,756			$	579,535

* As of March 31, 2018, the 2017 Credit Facility, due 2022

5.00% Senior Notes

2017 Credit Facility and Subsequent Amendment

As of March 31, 2019, the Company had $239,000 outstanding on the Amended 2017 Revolver and $438,315 under the Amended 2017 Term Loan.

2011 Credit Facility

Interest Rates on Long Term Debt

The weighted average interest rate on the long term debt at March 31, 2019 and March 31, 2018, was 4.1% and 3.7%, respectively.

Interest Paid

The Company paid in cash, $29,552, $23,527 and $20,781, net of interest received, for interest during the fiscal years ended March 31, 2019, 2018 and 2017, respectively.

Covenants

Short-Term Debt

Letters of Credit

As of March 31, 2019 and 2018, the Company had $3,955 and $3,074, respectively, of standby letters of credit.

Debt Issuance Costs

Available Lines of Credit

Leases

12 Months Ended

Mar. 31, 2019

Leases

The Company’s future minimum lease payments under operating leases that have noncancelable terms in excess of one year as of March 31, 2019 are as follows:




2020	$	31,483
2021	24,290
2022	16,514
2023	11,596
2024	8,683
Thereafter	23,757
Total minimum lease payments	$	116,323

Other Liabilities

12 Months Ended

Mar. 31, 2019

Other Liabilities

Other liabilities consist of the following:



	March 31,
	2019		2018
Tax Act - Transition Tax	$	55,489	$	89,700
Pension	39,924		44,404
Warranty	32,922		27,965
Liability for uncertain tax positions	20,240		1,684
Deferred income	—		7,094
Contract liabilities	6,360		—
Other	10,265		10,240
Total	$	165,200	$	181,087

Fair Value of Financial Instruments

12 Months Ended

Mar. 31, 2019

Recurring Fair Value Measurements

The following tables represent the financial assets and (liabilities) measured at fair value on a recurring basis as of March 31, 2019 and March 31, 2018 and the basis for that measurement:



	Total Fair Value Measurement March 31, 2019			Quoted Price in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Lead forward contracts	$	(902	)	$	—	$	(902	)	$	—
Foreign currency forward contracts	(249		)	—		(249		)	—
Total derivatives	$	(1,151	)	$	—	$	(1,151	)	$	—



	Total Fair Value Measurement March 31, 2018			Quoted Price in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Lead forward contracts	$	(3,877	)	$	—	$	(3,877	)	$	—
Foreign currency forward contracts	22			—		22			—
Total derivatives	$	(3,855	)	$	—	$	(3,855	)	$	—

Financial Instruments

The fair values of the Company’s cash and cash equivalents approximate carrying value due to their short maturities.

The carrying amounts and estimated fair values of the Company’s derivatives and Notes at March 31, 2019 and 2018 were as follows:



	March 31, 2019				March 31, 2018
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Financial assets:
Derivatives⁽¹⁾	$	—	$	—	$	22	$	22
Financial liabilities:
Notes ⁽²⁾	300,000		297,000		300,000		304,500
Derivatives⁽¹⁾	$	1,151	$	1,151	$	3,877	$	3,877


(1)	Represents lead and foreign currency forward contracts (see Note 12 for asset and liability positions of the lead and foreign currency forward contracts at March 31, 2019 and March 31, 2018).


(2)	The fair value amount of the Notes at March 31, 2019 and March 31, 2018 represent the trading value of the instruments.

Non-recurring fair value measurements

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivative Financial Instruments

12 Months Ended

Mar. 31, 2019

Derivatives in Cash Flow Hedging Relationships

Lead Forward Contracts

Foreign Currency Forward Contracts

Derivatives not Designated in Hedging Relationships

Foreign Currency Forward Contracts

Fair Value of Derivative Instruments

March 31, 2019 and 2018



	Derivatives and Hedging Activities Designated as Cash Flow Hedges				Derivatives and Hedging Activities Not Designated as Hedging Instruments
	March 31, 2019		March 31, 2018		March 31, 2019		March 31, 2018
Prepaid and other current assets:
Foreign currency forward contracts	—		209		—		—
Total assets	$	—	$	209	$	—	$	—
Accrued expenses:
Lead forward contracts	$	902	$	3,877	$	—	$	—
Foreign currency forward contracts	8		—		241		187
Total liabilities	$	910	$	3,877	$	241	$	187

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ended March 31, 2019



Derivatives Designated as Cash Flow Hedges	Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Lead forward contracts	$	(12,531	)	Cost of goods sold	$	(15,666	)
Foreign currency forward contracts	1,551			Cost of goods sold	385
Total	$	(10,980	)		$	(15,281	)



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivatives	Pretax Gain (Loss)
Foreign currency forward contracts	Other (income) expense, net	$	(1,856	)
Total		$	(1,856	)

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ended March 31, 2018



Derivatives Designated as Cash Flow Hedges	Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Lead forward contracts	$	(805	)	Cost of goods sold	$	5,860
Foreign currency forward contracts	(3,524		)	Cost of goods sold	(2,718		)
Total	$	(4,329	)		$	3,142



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivatives	Pretax Gain (Loss)
Foreign currency forward contracts	Other (income) expense, net	$	180
Total		$	180

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ended March 31, 2017



Derivatives Designated as Cash Flow Hedges	Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)		Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Lead forward contracts	$	7,907	Cost of goods sold	$	5,803
Foreign currency forward contracts	845		Cost of goods sold	433
Total	$	8,752		$	6,236



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivatives	Pretax Gain (Loss)
Foreign currency forward contracts	Other (income) expense, net	$	(471	)
Total		$	(471	)

Income Taxes

12 Months Ended

Mar. 31, 2019



	Fiscal year ended March 31,
	2019			2018			2017
Current income tax expense
Current:
Federal	$	6,377		$	115,315		$	30,362
State	5,027			3,461			4,855
Foreign	16,636			20,030			17,800
Total current income tax expense	28,040			138,806			53,017
Deferred income tax (benefit) expense
Federal	(5,031		)	(9,551		)	857
State	(669		)	789			590
Foreign	(756		)	(11,551		)	8
Total deferred income tax (benefit) expense	(6,456		)	(20,313		)	1,455
Total income tax expense	$	21,584		$	118,493		$	54,472

Earnings before income taxes consists of the following:



	Fiscal year ended March 31,
	2019		2018		2017
United States	$	53,339	$	74,440	$	80,436
Foreign	128,872		163,886		132,259
Earnings before income taxes	$	182,211	$	238,326	$	212,695

Income taxes paid by the Company for the fiscal years ended March 31, 2019, 2018 and 2017 were $53,866, $28,044 and $45,332, respectively.

U.S. Tax Cuts and Jobs Act of 2017

The following table sets forth the tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities:



	March 31,
	2019			2018
Deferred tax assets:
Accounts receivable	$	1,297		$	1,790
Inventories	4,081			3,660
Net operating loss carryforwards	48,423			50,928
Accrued expenses	21,574			21,274
Capitalized research and development costs	7,061			—
Other assets	17,656			16,832
Gross deferred tax assets	100,092			94,484
Less valuation allowance	(17,519		)	(15,255		)
Total deferred tax assets	82,573			79,229
Deferred tax liabilities:
Property, plant and equipment	25,656			21,045
Intangible assets	96,826			46,058
Other liabilities	1,737			1,331
Total deferred tax liabilities	124,219			68,434
Net deferred tax (liabilities) assets	$	(41,646	)	$	10,795

A reconciliation of income taxes at the statutory rate (21.0% for fiscal 2019, 31.55% for fiscal 2018 and 35% for fiscal 2017) to the income tax provision is as follows:



	Fiscal year ended March 31,
	2019			2018			2017
United States statutory income tax expense	$	38,264		$	75,196		$	74,444
Increase (decrease) resulting from:
Impact of Tax Act	(13,483		)	83,400			—
State income taxes, net of federal effect	3,285			3,146			3,677
Nondeductible expenses, domestic manufacturing deduction (fiscal 2018 and 2017) and other	2,677			1,078			1,993
Legal proceedings charge - European Competition Investigations - See Note 18	2,405			—			7,873
Net effect of GILTI, FDII, BEAT	2,320			—			—
Goodwill impairment - See Note 5	—			—			3,812
Effect of foreign operations	(16,763		)	(35,048		)	(39,377		)
Valuation allowance	2,879			(9,279		)	2,050
Income tax expense	$	21,584		$	118,493		$	54,472

Uncertain Tax Positions

The following table summarizes activity of the total amounts of unrecognized tax benefits:



	Fiscal year ended March 31,
	2019			2018			2017
Balance at beginning of year	$	1,568		$	1,450		$	2,375
Increases related to current year tax positions	129			397			252
Increases related to the Alpha acquisition	7,840			—			—
Increases related to prior year tax positions	11,463			11			31
Decreases related to prior tax positions and foreign currency translation	(544		)	—			(352		)
Decreases related to prior year tax positions settled	(93		)	(1		)	(678		)
Lapse of statute of limitations	(198		)	(289		)	(178		)
Balance at end of year	$	20,165		$	1,568		$	1,450

While the net effect on total unrecognized tax benefits cannot be reasonably estimated, approximately $2,275 is expected to reverse in fiscal 2020 due to expiration of various statute of limitations.

Retirement Plans

12 Months Ended

Mar. 31, 2019

Stockholders' Equity and Noncontrolling Interests [Abstract]

Retirement Plans

Defined Benefit Plans

The Company sponsors several retirement and pension plans covering eligible salaried and hourly employees. The Company uses a measurement date of March 31 for its pension plans.

Net periodic pension cost for fiscal 2019, 2018 and 2017, includes the following components:



	United States Plans									International Plans
	Fiscal year ended March 31,									Fiscal year ended March 31,
	2019			2018			2017			2019			2018			2017
Service cost	$	—		$	—		$	371		$	997		$	1,025		$	871
Interest cost	631			658			664			1,831			1,795			1,848
Expected return on plan assets	(514		)	(496		)	(816		)	(2,151		)	(2,264		)	(1,875		)
Amortization and deferral	184			303			453			1,520			1,468			978
Net periodic benefit cost	$	301		$	465		$	672		$	2,197		$	2,024		$	1,822



	United States Plans						International Plans
	March 31,						March 31,
	2019			2018			2019			2018
Change in projected benefit obligation
Benefit obligation at the beginning of the period	$	16,713		$	16,682		$	82,033		$	74,478
Service cost	—			—			997			1,025
Interest cost	631			658			1,831			1,795
Benefits paid, inclusive of plan expenses	(1,061		)	(1,037		)	(1,758		)	(2,153		)
Plan curtailments and settlements	—			—			(1,130		)	(52		)
Actuarial losses (gains)	364			410			(261		)	(2,705		)
Foreign currency translation adjustment	—			—			(6,674		)	9,645
Benefit obligation at the end of the period	$	16,647		$	16,713		$	75,038		$	82,033



Change in plan assets
Fair value of plan assets at the beginning of the period	$	13,928		$	12,731		$	38,757		$	34,323
Actual return on plan assets	758			1,731			2,109			688
Employer contributions	138			503			1,670			1,865
Benefits paid, inclusive of plan expenses	(1,061		)	(1,037		)	(1,758		)	(2,153		)
Plan curtailments and settlements	—			—			(1,130		)	(52		)
Foreign currency translation adjustment	—			—			(2,857		)	4,086
Fair value of plan assets at the end of the period	$	13,763		$	13,928		$	36,791		$	38,757
Funded status deficit	$	(2,884	)	$	(2,785	)	$	(38,247	)	$	(43,276	)



	March 31,
	2019			2018
Amounts recognized in the Consolidated Balance Sheets consist of:
Accrued expenses	(1,207		)	(1,657		)
Other liabilities	(39,924		)	(44,404		)
Total liabilities	$	(41,131	)	$	(46,061	)

The following table represents pension components (before tax) and related changes (before tax) recognized in AOCI for the Company’s pension plans for the years ended March 31, 2019, 2018 and 2017:



	Fiscal year ended March 31,
	2019			2018			2017
Amounts recorded in AOCI before taxes:
Prior service cost	$	(307	)	$	(385	)	$	(377	)
Net loss	(24,051		)	(27,762		)	(28,475		)
Net amount recognized	$	(24,358	)	$	(28,147	)	$	(28,852	)



	Fiscal year ended March 31,
	2019			2018			2017
Changes in plan assets and benefit obligations:
New prior service cost	$	—		$	—		$	—
Net loss (gain) arising during the year	(99		)	(1,953		)	5,485
Effect of exchange rates on amounts included in AOCI	(1,984		)	3,019			(2,275		)
Amounts recognized as a component of net periodic benefit costs:
Amortization of prior service cost	(45		)	(46		)	(42		)
Amortization or settlement recognition of net loss	(1,659		)	(1,725		)	(1,389		)
Total recognized in other comprehensive (income) loss	$	(3,787	)	$	(705	)	$	1,779

The amounts included in AOCI as of March 31, 2019 that are expected to be recognized as components of net periodic pension cost (before tax) during the next twelve months are as follows:



Prior service cost	$	(44	)
Net loss	(1,185		)
Net amount expected to be recognized	$	(1,229	)



	United States Plans				International Plans
	March 31,				March 31,
	2019		2018		2019		2018
All defined benefit plans:
Accumulated benefit obligation	$	16,647	$	16,713	$	71,350	$	77,724
Unfunded defined benefit plans:
Projected benefit obligation	$	—	$	—	$	32,320	$	33,124
Accumulated benefit obligation	—		—		30,328		31,270
Defined benefit plans with a projected benefit obligation in excess of the fair value of plan assets:
Projected benefit obligation	$	16,647	$	16,713	$	75,038	$	82,033
Fair value of plan assets	13,763		13,928		36,791		38,757
Defined benefit plans with an accumulated benefit obligation in excess of the fair value of plan assets:
Projected benefit obligation	$	16,647	$	16,713	$	74,235	$	81,253
Accumulated benefit obligation	16,647		16,713		70,654		77,021
Fair value of plan assets	13,763		13,928		36,077		37,986

Assumptions

Significant assumptions used to determine the net periodic benefit cost for the U.S. and International plans were as follows:



	United States Plans						International Plans
	Fiscal year ended March 31,						Fiscal year ended March 31,
	2019		2018		2017		2019	2018	2017
Discount rate	3.9	%	4.1	%	3.9	%	1.4-3.3%	1.5-3.5%	1.8-3.7%
Expected return on plan assets	6.3		6.8		7.0		4.1-6.0	3.6-6.3	3.3-6.5
Rate of compensation increase	N/A		N/A		N/A		1.8-4.0	1.5-4.0	1.5-4.0

N/A = not applicable

Significant assumptions used to determine the projected benefit obligations for the U.S. and International plans were as follows:



	United States Plans				International Plans
	March 31,				March 31,
	2019		2018		2019	2018
Discount rate	3.8	%	3.9	%	1.0-2.7%	1.4-3.3%
Rate of compensation increase	N/A		N/A		2.0-4.0	1.8-4.0

N/A = not applicable

The United States plans do not include compensation in the formula for determining the pension benefit as it is based solely on years of service.

Pension Plan Investment Strategy

The following table represents the Company's pension plan investments measured at fair value as of March 31, 2019 and 2018 and the basis for that measurement:



	March 31, 2019
	United States Plans								International Plans
	Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Asset category:
Cash and cash equivalents	$	1,080	$	1,080	$	—	$	—	$	83	$	83	$	—	$	—
Equity securities
US^(a)	8,275		8,275		—		—		—		—		—		—
International^(b)	—		—		—		—		23,875		—		23,875		—
Fixed income^(c)	4,408		4,408		—		—		12,833		—		12,833		—
Total	$	13,763	$	13,763	$	—	$	—	$	36,791	$	83	$	36,708	$	—



	March 31, 2018
	United States Plans								International Plans
	Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Asset category:
Cash and cash equivalents	$	891	$	891	$	—	$	—	$	49	$	49	$	—	$	—
Equity securities
US^(a)	9,864		9,864		—		—		—		—		—		—
International^(b)	—		—		—		—		25,768		—		25,768		—
Fixed income^(c)	3,173		3,173		—		—		12,940		—		12,940		—
Total	$	13,928	$	13,928	$	—	$	—	$	38,757	$	49	$	38,708	$	—

The fair values presented above were determined based on valuation techniques to measure fair value as discussed in Note 1.


(a)	US equities include companies that are well diversified by industry sector and equity style (i.e., growth and value strategies). Active and passive management strategies are employed. Investments are primarily in large capitalization stocks and, to a lesser extent, mid- and small-cap stocks.


(b)	International equities are invested in companies that are traded on exchanges outside the U.S. and are well diversified by industry sector, country and equity style. Active and passive strategies are employed. The vast majority of the investments are made in companies in developed markets with a small percentage in emerging markets.


(c)	Fixed income consists primarily of investment grade bonds from diversified industries.

The Company expects to make cash contributions of approximately $1,640 to its pension plans in fiscal 2020.

Estimated future benefit payments under the Company’s pension plans are as follows:




2020	$	2,713
2021	2,783
2022	3,072
2023	3,392
2024	3,536
Years 2025-2029	21,106

Defined Contribution Plan

Stockholders' Equity and Noncontrolling Interests

12 Months Ended

Mar. 31, 2019

Stockholders' Equity and Noncontrolling Interests

Stockholders’ Equity and Noncontrolling Interests

Preferred Stock and Common Stock

The following summarizes the change in the number of shares of common stock outstanding during fiscal years ended March 31, 2017, 2018 and 2019, respectively:




Shares outstanding as of March 31, 2016	43,189,502
Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes	258,034
Shares outstanding as of March 31, 2017	43,447,536
Purchase of treasury stock	(1,756,831	)
Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes	224,295
Shares outstanding as of March 31, 2018	41,915,000
Purchase of treasury stock	(726,347	)
Shares issued towards purchase consideration of Alpha acquisition	1,177,630
Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes	254,467
Shares outstanding as of March 31, 2019	42,620,750

Treasury Stock

Treasury Stock Reissuance

Accumulated Other Comprehensive Income (“AOCI”)

The components of AOCI, net of tax, are as follows:



	Beginning Balance			Before Reclassifications			Amount Reclassified from AOCI			Ending Balance
March 31, 2019
Pension funded status adjustment	$	(22,503	)	$	339		$	1,373		$	(20,791	)
Net unrealized gain (loss) on derivative instruments	(3,425		)	(8,396		)	11,691			(130		)
Foreign currency translation adjustment	(15,789		)	(105,972		)	—			(121,761		)
Accumulated other comprehensive loss	$	(41,717	)	$	(114,029	)	$	13,064		$	(142,682	)
March 31, 2018
Pension funded status adjustment	$	(25,555	)	$	1,692		$	1,360		$	(22,503	)
Net unrealized gain (loss) on derivative instruments	1,975			(2,868		)	(2,532		)	(3,425		)
Foreign currency translation adjustment	(129,244		)	113,455			—			(15,789		)
Accumulated other comprehensive loss	$	(152,824	)	$	112,279		$	(1,172	)	$	(41,717	)
March 31, 2017
Pension funded status adjustment	$	(21,861	)	$	(4,659	)	$	965		$	(25,555	)
Net unrealized gain (loss) on derivative instruments	388			5,523			(3,936		)	1,975
Foreign currency translation adjustment	(75,876		)	(53,368		)	—			(129,244		)
Accumulated other comprehensive loss	$	(97,349	)	$	(52,504	)	$	(2,971	)	$	(152,824	)

The following table presents reclassifications from AOCI during the twelve months ended March 31, 2019:



Components of AOCI	Amounts Reclassified from AOCI			Location of (Gain) Loss Recognized on Income Statement
Derivatives in Cash Flow Hedging Relationships:
Net unrealized loss on derivative instruments	$	15,281		Cost of goods sold
Tax benefit	(3,590		)
Net unrealized loss on derivative instruments, net of tax	$	11,691

Defined benefit pension costs:
Prior service costs and deferrals	$	1,704		Net periodic benefit cost, included in other (income) expense, net - See Note 1 and 14
Tax benefit	(331		)
Net periodic benefit cost, net of tax	$	1,373

The following table presents reclassifications from AOCI during the twelve months ended March 31, 2018:



Components of AOCI	Amounts Reclassified from AOCI			Location of (Gain) Loss Recognized on Income Statement
Derivatives in Cash Flow Hedging Relationships:
Net unrealized gain on derivative instruments	$	(3,142	)	Cost of goods sold
Tax expense	610
Net unrealized gain on derivative instruments, net of tax	$	(2,532	)

Defined benefit pension costs:
Prior service costs and deferrals	$	1,771		Net periodic benefit cost, included in other (income) expense, net - See Note 1 and 14
Tax benefit	(411		)
Net periodic benefit cost, net of tax	$	1,360

The following table presents reclassifications from AOCI during the twelve months ended March 31, 2017:



Components of AOCI	Amounts Reclassified from AOCI			Location of (Gain) Loss Recognized on Income Statement
Derivatives in Cash Flow Hedging Relationships:
Net unrealized gain on derivative instruments	$	(6,236	)	Cost of goods sold
Tax expense	2,300
Net unrealized gain on derivative instruments, net of tax	$	(3,936	)

Defined benefit pension costs:
Prior service costs and deferrals	$	1,431		Net periodic benefit cost, included in other (income) expense, net - See Note 1 and 14
Tax benefit	(466		)
Net periodic benefit cost, net of tax	$	965

Redeemable Noncontrolling Interests

In fiscal 2017, the Company deconsolidated its joint venture in South Africa and the impact of this deconsolidation was reflected in the Consolidated Statements of Income.

The following demonstrates the change in redeemable noncontrolling interests during the fiscal year ended March 31, 2017:




Balance as of March 31, 2016	$	5,997
Net losses attributable to redeemable noncontrolling interests	(2,021		)
Deconsolidation of joint venture	(4,035		)
Foreign currency translation adjustment	59
Balance as of March 31, 2017	$	—

Stock-Based Compensation

12 Months Ended

Mar. 31, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation

Stock Options

For purposes of determining the fair value of stock options granted, the Company used a Black-Scholes Model with the following assumptions:



	2019		2018		2017
Risk-free interest rate	2.77	%	2.08	%	1.41	%
Dividend yield	0.93	%	0.84	%	1.22	%
Expected life (years)	6		6		6
Volatility	26.8	%	29.2	%	30.4	%

The following table summarizes the Company’s stock option activity in the years indicated:



	Number of Options		Weighted- Average Remaining Contract Term (Years)	Weighted- Average Exercise Price		Aggregate Intrinsic Value
Options outstanding as of March 31, 2016	210,297		8.5	$	67.54	$	218
Granted	242,068			57.60		—
Exercised	(263	)		18.25		12
Expired	(434	)		18.25		15
Options outstanding as of March 31, 2017	451,668		8.4	$	62.29	$	7,520
Granted	169,703			83.14		—
Exercised	(62,197	)		63.44		1,132
Forfeited	(11,495	)		70.22		75
Expired	(2,089	)		18.25		137
Options outstanding as of March 31, 2018	545,590		8.4	$	68.65	$	2,679
Granted	192,700			75.17		—
Exercised	(171,630	)		63.66		2,707
Forfeited	(11,754	)		75.17		—
Options outstanding as of March 31, 2019	554,906		8.0	$	72.31	$	1,040
Options exercisable as of March 31, 2019	186,823		6.9	$	69.34	$	452
Options vested and expected to vest, as of March 31, 2019	545,299		8.0	$	72.24	$	1,038

The following table summarizes information regarding stock options outstanding as of March 31, 2019:




Range of Exercise Prices	Number of Options	Weighted- Average Remaining Contractual Life (Years)	Weighted- Average Exercise Price
$55.00-$60.00	137,599	7.1	$	57.60
$65.01-$70.00	73,368	5.8	$	68.82
$75.01-$83.14	343,939	8.8	$	78.95
	554,906	8.0	$	72.31

Restricted Stock Units, Market and Performance-condition based Awards

Non-employee directors

Employees

For purposes of determining the fair value of TSRs granted in fiscal 2019, fiscal 2018, and fiscal 2017, the Company used a Monte Carlo Simulation with the following assumptions:



	2019		2018		2017
Risk-free interest rate	2.66	%	1.57	%	0.94	%
Dividend yield	—	%	—	%	—	%
Expected life (years)	3		3		3
Volatility	26.41	%	27.49	%	31.74	%



	Restricted Stock Units (RSU)				Market condition-based Share Units (TSR)				Performance condition-based Share Units (PSU)
	Number of RSU		Weighted- Average Grant Date Fair Value		Number of TSR		Weighted- Average Grant Date Fair Value		Number of PSU		Weighted- Average Grant Date
Non-vested awards as of March 31, 2018	633,751		$	56.60	349,941		$	70.22	—		$	—
Granted	241,105		69.43		36,646		85.84		45,883		68.48
Stock dividend	6,087		56.81		3,131		72.60		320		68.48
Performance factor	—		—		143		75.48		—		—
Vested	(148,487	)	68.55		(3,482	)	59.94		—		—
Canceled	(10,809	)	72.56		(33,795	)	62.21		(3,677	)	68.48
Non-vested awards as of March 31, 2019	721,647		$	57.72	352,584		$	72.83	42,526		$	68.48

All Award Plans

Earnings Per Share

12 Months Ended

Mar. 31, 2018

Restructuring and Related Activities [Abstract]



	Fiscal year ended March 31,
	2019		2018		2017
Net earnings attributable to EnerSys stockholders	$	160,239	$	119,594	$	160,214
Weighted-average number of common shares outstanding:
Basic	42,335,023		42,612,036		43,389,333
Dilutive effect of:
Common shares from exercise and lapse of equity awards, net of shares assumed reacquired	673,929		507,820		623,210
Diluted weighted-average number of common shares outstanding	43,008,952		43,119,856		44,012,543
Basic earnings per common share attributable to EnerSys stockholders	$	3.79	$	2.81	$	3.69
Diluted earnings per common share attributable to EnerSys stockholders	$	3.73	$	2.77	$	3.64
Anti-dilutive equity awards not included in diluted weighted-average common shares	355,728		59,482		1,295

Commitments, Contingencies and Litigation	12 Months Ended
Commitments, Contingencies and Litigation	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Litigation	Commitments, Contingencies and Litigation Litigation and Other Legal Matters In the ordinary course of business, the Company and its subsidiaries are routinely defendants in or parties to pending and threatened legal actions and proceedings, including actions brought on behalf of various classes of claimants. These actions and proceedings are generally based on alleged violations of environmental, anticompetition, employment, contract and other laws. In some of these actions and proceedings, claims for substantial monetary damages are asserted against the Company and its subsidiaries. In the ordinary course of business, the Company and its subsidiaries are also subject to regulatory and governmental examinations, information gathering requests, inquiries, investigations, and threatened legal actions and proceedings. In connection with formal and informal inquiries by federal, state, local and foreign agencies, the Company and its subsidiaries receive numerous requests, subpoenas and orders for documents, testimony and information in connection with various aspects of their activities. European Competition Investigations Certain of the Company’s European subsidiaries had received subpoenas and requests for documents and, in some cases, interviews from, and have had on-site inspections conducted by the competition authorities of Belgium, Germany and the Netherlands relating to conduct and anticompetitive practices of certain industrial battery participants. The Company settled the Belgian regulatory proceeding in February 2016 by acknowledging certain anticompetitive practices and conduct and agreeing to pay a fine of $1,962, which was paid in March 2016. During fiscal 2019, the Company paid $2,402 towards certain aspects of this matter, which are under appeal. As of March 31, 2019 and March 31, 2018, the Company had a reserve balance of $0 and $2,326, respectively. In June 2017, the Company settled a portion of its previously disclosed proceeding involving the German competition authority relating to conduct involving the Company's motive power battery business and agreed to pay a fine of $14,811, which was paid in July 2017. Also in June 2017, the German competition authority issued a fining decision related to the Company's reserve power battery business, which constitutes the remaining portion of the previously disclosed German proceeding. The Company had appealed this decision. In March 2019, the Company settled this matter by agreeing to pay $7,258, which was paid in April 2019. As of March 31, 2019 and March 31, 2018, the Company had a reserve balance of $7,258 and $0, respectively. In July 2017, the Company settled the Dutch regulatory proceeding and agreed to pay a fine of $11,229, which was paid in August 2017. As of March 31, 2019 and March 31, 2018, the Company had a total reserve balance of $7,258 and $2,326, respectively, in connection with these investigations and other related legal matters, included in accrued expenses on the Consolidated Balance Sheets. The foregoing estimate of losses is based upon currently available information for these proceedings. However, the precise scope, timing and time period at issue, as well as the final outcome of the investigations or customer claims, remain uncertain. Accordingly, the Company’s estimate may change from time to time, and actual losses could vary. EnerSys Sarl Litigation One of the parties to a litigation related to a 1999 fire in a French hotel under construction involving the Company’s French subsidiary, EnerSys Sarl, which was acquired by the Company in 2002, that was adverse to the Company, appealed the ruling by the Court of Appeal of Lyon on June 11, 2013, which ruled in the Company’s favor, entitling the Company to a refund of the monies paid of €2,000, or $2,756 to the French Supreme Court, which appeal was denied in January 2015. During the third quarter of fiscal 2019, the Company and the adverse party settled this final item with the Company receiving a refund, including interest, from the adverse party of €2,500, or $2,843, for monies paid. The Company believes that it has no further liability with respect to this matter. Environmental Issues As a result of its operations, the Company is subject to various federal, state and local, as well as international environmental laws and regulations and is exposed to the costs and risks of registering, handling, processing, storing, transporting, and disposing of hazardous substances, especially lead and acid. The Company’s operations are also subject to federal, state, local and international occupational safety and health regulations, including laws and regulations relating to exposure to lead in the workplace. The Company is responsible for certain cleanup obligations at the former Yuasa battery facility in Sumter, South Carolina that predates its ownership of this facility. This manufacturing facility was closed in 2001 and the Company established a reserve for this facility which was $1,081 and $1,109 as of March 31, 2019 and 2018, respectively. Based on current information, the Company’s management believes this reserve is adequate to satisfy the Company’s environmental liabilities at this facility. This facility is separate from the Company’s current metal fabrication facility in Sumter. Collective Bargaining At March 31, 2019, the Company had approximately 11,000 employees. Of these employees, approximately 27% were covered by collective bargaining agreements. Employees covered by collective bargaining agreements that expire in the next twelve months were approximately 10% of the total workforce. The average term of these agreements is 2 years, with the longest term being 3 years. The Company considers its employee relations to be good and did not experience any significant labor unrest or disruption of production during fiscal 2019. Lead and Foreign Currency Forward Contracts To stabilize its lead costs and reduce volatility from currency movements, the Company enters into contracts with financial institutions. The vast majority of such contracts are for a period not extending beyond one year. Please refer to Note 12 - Derivative Financial Instruments for more details. Other The Company has various purchase and capital commitments incidental to the ordinary conduct of business. In the aggregate, such commitments are not at prices in excess of current market.

Restructuring Plans and Other Exit Charges

12 Months Ended

Mar. 31, 2019

Restructuring Plans and Other Exit Charges

Restructuring and Other Exit Charges

Restructuring Plans

A roll-forward of the restructuring reserve is as follows:



	Employee Severance			Other			Total
Balance at March 31, 2016	$	2,964		$	25		$	2,989
Accrued	4,566			742			5,308
Costs incurred	(4,754		)	(604		)	(5,358		)
Foreign currency impact and other	(108		)	(19		)	(127		)
Balance at March 31, 2017	$	2,668		$	144		$	2,812
Accrued	4,757			445			5,202
Costs incurred	(4,849		)	(574		)	(5,423		)
Foreign currency impact and other	317			1			318
Balance at March 31, 2018	$	2,893		$	16		$	2,909
Accrued	6,554			1,639			8,193
Costs incurred	(6,893		)	(1,086		)	(7,979		)
Foreign currency impact and other	(198		)	27			(171		)
Balance at March 31, 2019	$	2,356		$	596		$	2,952

Other Exit Charges

During fiscal 2018, the Company wrote off $3,457 of inventories, relating to the closing of its Cleveland, Ohio charger manufacturing facility, which was reported in cost of goods sold.

Warranty

12 Months Ended

Mar. 31, 2019

Warranty



	Fiscal year ended March 31,
	2019			2018			2017
Balance at beginning of year	$	50,602		$	46,116		$	48,422
Current year provisions	23,679			21,706			17,852
Costs incurred	(25,053		)	(18,820		)	(15,945		)
Warranty reserves of acquired business - Alpha	7,535			—			—
Foreign currency translation adjustment	(2,195		)	1,600			(4,213		)
Balance at end of year	$	54,568		$	50,602		$	46,116

Other (Income) Expense, Net

12 Months Ended

Mar. 31, 2019

Other (Income) Expense, Net

Other (income) expense, net consists of the following:



	Fiscal year ended March 31,
	2019			2018		2017
Foreign exchange transaction (gains) losses	$	(3,044	)	$	5,499	$	(662	)
Non-service components of pension expense	1,502			1,464		1,252
Other	928			556		1,631
Total	$	(614	)	$	7,519	$	2,221

Business Segments

12 Months Ended

Mar. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

Business Segments

Summarized financial information related to the Company’s reportable segments at March 31, 2019, 2018 and 2017 and for each of the fiscal years then ended is shown below.



	Fiscal year ended March 31,
	2019			2018			2017
Net sales by segment to unaffiliated customers
Americas	$	1,690,912		$	1,429,888		$	1,332,353
EMEA	860,563			849,420			763,013
Asia	256,542			302,583			271,783
Total net sales	$	2,808,017		$	2,581,891		$	2,367,149
Net sales by product line
Reserve power	$	1,416,173		$	1,247,900		$	1,142,327
Motive power	1,391,844			1,333,991			1,224,822
Total net sales	$	2,808,017		$	2,581,891		$	2,367,149
Intersegment sales
Americas	$	28,753		$	29,513		$	26,039
EMEA	123,274			133,164			93,150
Asia	34,531			23,375			22,584
Total intersegment sales⁽¹⁾	$	186,558		$	186,052		$	141,773
Operating earnings by segment
Americas	$	186,814		$	189,466		$	191,801
EMEA	71,963			77,671			77,376
Asia	3,213			12,647			14,994
Inventory step up to fair value relating to acquisition - Americas	(7,263		)	—			—
Inventory adjustment relating to exit activities - Americas	—			(3,457		)	—
Inventory adjustment relating to exit activities - EMEA	(2,590		)	—			(2,157		)
Inventory adjustment relating to exit activities - Asia	(526		)	—			—
Restructuring charges - Americas	(4,066		)	(1,246		)	(892		)
Restructuring and other exit charges - EMEA	(26,989		)	(4,023		)	(5,487		)
Restructuring charges - Asia	(3,654		)	(212		)	(781		)
Impairment of goodwill and indefinite-lived intangibles - Americas	—			—			(9,346		)
Impairment of goodwill and indefinite-lived intangibles - EMEA	—			—			(4,670		)
Legal proceedings charge, net - EMEA	(4,437		)	—			(23,725		)
Total operating earnings⁽²⁾	$	212,465		$	270,846		$	237,113
Property, plant and equipment, net
Americas	$	257,559		$	210,998		$	190,169
EMEA	94,932			118,263			100,042
Asia	56,948			60,999			58,338
Total	$	409,439		$	390,260		$	348,549
Capital Expenditures
Americas	$	45,029		$	46,905		$	34,809
EMEA	18,972			18,392			13,733
Asia	6,371			4,535			1,530
Total	$	70,372		$	69,832		$	50,072
Depreciation and Amortization
Americas	$	40,675		$	30,421		$	30,204
EMEA	15,128			16,198			15,693
Asia	7,545			7,698			8,048
Total	$	63,348		$	54,317		$	53,945


(1)	Intersegment sales are presented on a cost-plus basis which takes into consideration the effect of transfer prices between legal entities.


(2)	The Company does not allocate interest expense or other (income) expense, net, to the reportable segments.

Quarterly Financial Data (Unaudited)

12 Months Ended

Mar. 31, 2018

Quarterly Financial Data (Unaudited)



	1st Quarter		2nd Quarter		3rd Quarter			4th Quarter		Fiscal Year
Fiscal year ended March 31, 2019
Net sales	$	670,930	$	660,462	$	680,022		$	796,603	$	2,808,017
Gross profit	165,334		160,880		164,546			202,266		693,026
Operating earnings^(1)(3)(5)	64,179		63,357		49,951			34,978		212,465
Net earnings⁽⁶⁾	46,020		47,447		48,614			18,546		160,627
Net earnings attributable to EnerSys stockholders	45,860		47,424		48,417			18,538		160,239
Net earnings per common share attributable to EnerSys stockholders—basic	$	1.09	$	1.13	$	1.14		$	0.43	$	3.79
Net earnings per common share attributable to EnerSys stockholders—diluted	$	1.08	$	1.11	$	1.12		$	0.42	$	3.73
Fiscal year ended March 31, 2018
Net sales	$	622,625	$	617,289	$	658,935		$	683,042	$	2,581,891
Gross profit	163,458		160,248		167,310			167,388		658,404
Operating earnings⁽²⁾⁽⁴⁾	69,972		64,364		68,785			67,725		270,846
Net earnings (loss)⁽⁷⁾	48,322		43,151		(25,779		)	54,139		119,833
Net earnings (loss) attributable to EnerSys stockholders	48,201		43,222		(25,847		)	54,018		119,594
Net earnings (loss) per common share attributable to EnerSys stockholders—basic	$	1.11	$	1.01	$	(0.61	)	$	1.29	$	2.81
Net earnings (loss) per common share attributable to EnerSys stockholders—diluted	$	1.09	$	1.00	$	(0.61	)	$	1.27	$	2.77


(1)	Included in Operating earnings were inventory adjustment relating to exit activities of $526 and $2,590 in the first and fourth quarter of fiscal 2019, respectively. Also included were inventory adjustments relating to Alpha acquisition of $3,747 and $3,516 in the third and fourth quarter of fiscal 2019, respectively.


(2)	Included in Operating earnings were inventory adjustment relating to exit activities of $3,457 in the fourth quarter of fiscal 2018, respectively.


(3)	Included in Operating earnings were restructuring and other exit charges of $1,739, $1,121, $5,392 and $26,457 for the first, second, third and fourth quarters of fiscal 2019, respectively.


(4)	Included in Operating earnings were restructuring and other exit charges of $833, $1,776, $1,808 and $1,064 for the first, second, third and fourth quarters of fiscal 2018, respectively.


(5)	Included in Operating earnings were legal proceedings settlement income of $2,843 in the third quarter and expense of $7,280 in the fourth quarter of fiscal 2019.


(6)	Included in net earnings was a tax benefit of $13,483 for the third quarter of fiscal 2019, on account of the Tax Act.

(7)

Included in net earnings (loss) was tax expense of $77,347 and $4,106 for the third and fourth quarters of fiscal 2018, respectively, on account of the Tax Act.

Subsequent Events	12 Months Ended
Subsequent Events	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On May 16, 2019, the Company announced the payment of a quarterly cash dividend of $0.175 per share of common stock to be paid on June 28, 2019, to stockholders of record as of June 14, 2019.

Valuation and Qualifying Accounts

12 Months Ended

Mar. 31, 2019

SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]

Valuation and Qualifying Accounts



	Balance at Beginning of Period		Additions Charged to Expense		Write-Offs Net of Recoveries			Other⁽¹⁾			Balance at End of Period
Allowance for doubtful accounts:
Fiscal year ended March 31, 2017	$	11,393	$	1,794	$	(173	)	$	(352	)	$	12,662
Fiscal year ended March 31, 2018	12,662		822		(1,400		)	559			12,643
Fiscal year ended March 31, 2019	12,643		1,385		(2,459		)	(756		)	10,813

Tax Valuation Allowance



	Balance at Beginning of Period		Additions Charged to Expense		Valuation Allowance Reversal			Business Combination Adjustments		Other^{(1) (2) (3)}			Balance at End of Period
Deferred tax asset—valuation allowance:
Fiscal year ended March 31, 2017	$	25,416	$	4,305	$	(2,255	)	$	—	$	(413	)	$	27,053
Fiscal year ended March 31, 2018	27,053		4,853		(14,132		)	—		(2,519		)	15,255
Fiscal year ended March 31, 2019	15,255		2,978		(99		)	1,157		(1,772		)	17,519


(1)	Primarily the impact of currency changes.


(2)	In fiscal 2019, “Other” included expiration of net operating losses for which a full valuation allowance was recorded.

(3)

In fiscal 2018, “Other” also included an offset to adjustments to foreign net operating losses for which a full valuation allowance was recorded.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Mar. 31, 2019

Principles of Consolidation

Description of Business

Foreign Currency Translation

Revenue Recognition

ASC 606, Revenue from Contracts with Customers, was adopted for the fiscal year beginning April 1, 2018.

Concurrent with the adoption of the new standard, the Company has updated its revenue recognition policy as follows:

The Company determines revenue recognition by applying the following steps:

1. identify the contract with a customer;

2. identify the performance obligations in the contract;

3. determine the transaction price;

4. allocate the transaction price to the performance obligations; and

5. recognize revenue as the performance obligations are satisfied.

The Company's primary performance obligation to its customers is the delivery of finished goods and products, pursuant to

purchase orders. Control of the products sold typically transfers to its customers at the point in time when the goods are shipped

as this is also when title generally passes to its customers under the terms and conditions of our customer arrangements.

The Company's typical payment terms are 30 days and sales arrangements do not contain any significant financing component for its customers.

The Company applies a policy election to exclude transaction taxes collected from customers from sales when the tax is both imposed on and concurrent with a specific revenue-producing transaction.

Warranties

Cash and Cash Equivalents

Cash and cash equivalents include all highly liquid investments with an original maturity of three months or less when purchased.

Concentration of Credit Risk

Accounts Receivable

Inventories are stated at the lower of cost or market. Cost is determined using the first-in, first-out (FIFO) method. The cost of inventory consists of material, labor, and associated overhead.

Maintenance and repairs are expensed as incurred. Interest on capital projects is capitalized during the construction period.

Business Combinations

intangible assets is recorded to goodwill. The results of operations of the acquired business are included in the Company’s operating results from the date of acquisition.

Impairment of Long-Lived Assets

Environmental Expenditures

The Company does not have any credit-related contingent features associated with its derivative instruments.

The Company groups its recurring, non-recurring and disclosure-only fair value measurements into the following levels when making fair value measurement disclosures:



Level 1		Inputs are unadjusted quoted prices in active markets for identical assets or liabilities.

Level 2		Inputs are quoted prices for similar assets or liabilities in an active market, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable and market-corroborated inputs which are derived principally from or corroborated by observable market data.

Level 3		Inputs are derived from valuation techniques in which one or more significant inputs or value drivers are unobservable.

Stock-Based Compensation Plans

The Company recognizes tax related interest and penalties in income tax expense in its Consolidated Statement of Income.

Deferred Financing Fees

Market and Performance condition-based awards

The Company grants market condition-based awards and performance condition-based awards.

Restricted Stock Units

Stock Options

New Accounting Pronouncements

Segment Reporting


•	Americas, which includes North and South America, with segment headquarters in Reading, Pennsylvania, U.S.A.,


•	EMEA, which includes Europe, the Middle East and Africa, with segment headquarters in Zug, Switzerland, and

•

Asia, which includes Asia, Australia and Oceania, with segment headquarters in Singapore.

Accounting Pronouncements

Accounting Pronouncements Issued But Not Adopted as of March 31, 2019


•	to adopt the optional transition method defined within ASU 2018-11 and not restate comparative prior periods but instead recognize a cumulative effect adjustment to the opening balance of retained earnings in the period of adoption;


•	to elect the package of three practical expedients addressing whether a contract contains a lease, lease classification and initial direct costs;

to combine lease and non-lease components as a single component for all asset classes;


•	to use a portfolio approach to determine the incremental borrowing rate; and


•	to apply the short-term lease exception to leases that, at the commencement date, has a lease term of 12 months or less and does not include an option to purchase the underlying asset that the lessee is reasonably certain to exercise.

Use of Estimates

Acquisition (Tables)

12 Months Ended

Mar. 31, 2019

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed

The acquired assets and assumed liabilities include the following:



Accounts receivable	$	115,467
Inventories	84,297
Other current assets	6,822
Other intangible assets	332,000
Property, plant and equipment	20,987
Other assets	9,005
Total assets acquired	$	568,578
Accounts payable	35,803
Accrued liabilities	41,918
Deferred income taxes	56,331
Other liabilities	12,642
Total liabilities assumed	$	146,694
Net assets acquired	$	421,884

Purchase price:
Cash paid for net assets acquired	$	650,000
Fair value of shares issued for net assets acquired	93,268
Working capital adjustment	(766		)
Total purchase consideration	742,502
Less: Fair value of acquired identifiable assets and liabilities	421,884
Goodwill	$	320,618

Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination

The following table summarizes the estimated fair value of Alpha's identifiable intangible assets and the initial assessment of their respective estimated lives:



	Type	Life in Years	Fair Value
Trademarks	Indefinite-lived	Indefinite	$	56,000
Customer relationships	Finite-lived	14	221,000
Technology	Finite-lived	10	55,000
Total identifiable intangible assets			$	332,000

Business Acquisition, Pro Forma Information

The following unaudited summary information is presented on a consolidated pro forma basis as if the acquisition had occurred on April 1, 2017:



	Fiscal year ended
	March 31, 2019		March 31, 2018
Net sales	$	3,278,646	$	3,124,527
Net earnings attributable to EnerSys stockholders	207,904		126,965
Net earnings per share attributable to EnerSys stockholders - basic	4.79		2.90
Net earnings per share attributable to EnerSys stockholders - assuming dilution	4.71		2.87

Inventories (Tables)

12 Months Ended

Mar. 31, 2019

Summary Of Net Inventories



	March 31,
	2019		2018
Raw materials	$	138,718	$	92,216
Work-in-process	129,736		136,068
Finished goods	235,415		185,950
Total	$	503,869	$	414,234

Property, Plant, and Equipment (Tables)

12 Months Ended

Mar. 31, 2019

Summary Of Property, Plant, And Equipment

Property, plant, and equipment consist of:



	March 31,
	2019			2018
Land, buildings, and improvements	$	268,006		$	273,506
Machinery and equipment	683,955			657,262
Construction in progress	54,278			49,900
	1,006,239			980,668
Less accumulated depreciation	(596,800		)	(590,408		)
Total	$	409,439		$	390,260

Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Mar. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule Of Company's Other Intangible Assets

Information regarding the Company’s other intangible assets are as follows:



	March 31,
	2019							2018
	Gross Amount		Accumulated Amortization			Net Amount		Gross Amount		Accumulated Amortization			Net Amount
Indefinite-lived intangible assets:
Trademarks	$	152,484	$	(953	)	$	151,531	$	97,444	$	(953	)	$	96,491
Finite-lived intangible assets:
Customer relationships	286,664		(42,704		)	243,960		66,973		(31,500		)	35,473
Non-compete	3,025		(2,807		)	218		2,852		(2,759		)	93
Technology	77,779		(12,229		)	65,550		22,769		(8,872		)	13,897
Trademarks	2,003		(1,236		)	767		2,003		(1,151		)	852
Licenses	1,477		(1,187		)	290		1,491		(1,156		)	335
Total	$	523,432	$	(61,116	)	$	462,316	$	193,532	$	(46,391	)	$	147,141

Schedule Of Changes In The Carrying Amount Of Goodwill By Business Segment

The changes in the carrying amount of goodwill by reportable segment are as follows:



	Fiscal year ended March 31, 2019
	Americas			EMEA			Asia			Total
Balance at beginning of year	$	151,255		$	155,825		$	45,725		$	352,805
Acquisitions during the year	320,618			—			—			320,618
Foreign currency translation adjustment	(1,679		)	(12,556		)	(2,789		)	(17,024		)
Balance at end of year	$	470,194		$	143,269		$	42,936		$	656,399



	Fiscal year ended March 31, 2018
	Americas		EMEA		Asia		Total
Balance at beginning of year	$	146,982	$	138,813	$	42,862	$	328,657
Acquisitions during the year	3,670		—		—		3,670
Foreign currency translation adjustment	603		17,012		2,863		20,478
Balance at end of year	$	151,255	$	155,825	$	45,725	$	352,805

A reconciliation of goodwill and accumulated goodwill impairment losses, by reportable segment, is as follows:



	March 31, 2019
	Americas			EMEA			Asia			Total
Gross carrying value	$	528,039		$	149,422		$	48,115		$	725,576
Accumulated goodwill impairment charges	(57,845		)	(6,153		)	(5,179		)	(69,177		)
Net book value	$	470,194		$	143,269		$	42,936		$	656,399



	March 31, 2018
	Americas			EMEA			Asia			Total
Gross carrying value	$	209,100		$	161,978		$	50,904		$	421,982
Accumulated goodwill impairment charges	(57,845		)	(6,153		)	(5,179		)	(69,177		)
Net book value	$	151,255		$	155,825		$	45,725		$	352,805

Prepaid and Other Current Assets (Tables)

12 Months Ended

Mar. 31, 2019

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Schedule Of Prepaid And Other Current Assets

Prepaid and other current assets consist of the following:



	March 31,
	2019		2018
Contract assets	$	38,778	$	—
Prepaid non-income taxes	22,490		22,583
Non-trade receivables	10,823		4,087
Prepaid income taxes	9,608		8,921
Other	27,732		21,319
Total	$	109,431	$	56,910

Accrued Expenses (Tables)

12 Months Ended

Mar. 31, 2019

Summary Of Accrued Expenses

Accrued expenses consist of the following:



	March 31,
	2019		2018
Payroll and benefits	$	54,285	$	50,053
Accrued selling expenses	35,394		34,831
Warranty	21,646		22,637
VAT and other non-income taxes	17,125		13,155
Project related accruals	16,301		—
Contract liabilities	15,162		—
Freight	14,423		15,810
Income taxes payable	9,234		19,696
Legal proceedings	7,258		2,326
Interest	7,248		6,762
Tax Act - Transition Tax	5,290		7,800
Restructuring	2,952		2,909
Pension	1,207		1,657
Deferred income	—		9,387
Other	48,356		27,095
Total	$	255,881	$	214,118

Debt (Tables)

12 Months Ended

Mar. 31, 2019

Schedule Of Long-Term Debt

The following summarizes the Company’s long-term debt:



	As of March 31,
	2019				2018
	Principal		Unamortized Issuance Costs		Principal		Unamortized Issuance Costs
5.00% Senior Notes, due 2023	$	300,000	$	2,497	$	300,000	$	3,122
Amended Credit Facility, due 2022^*	677,315		3,062		285,500		2,843
	$	977,315	$	5,559	$	585,500	$	5,965
Less: Unamortized issuance costs	5,559				5,965
Less: Current portion	—				—
Long-term debt, net of unamortized issuance costs	$	971,756			$	579,535

Leases (Tables)

12 Months Ended

Mar. 31, 2019

Schedule Of Capital And Operating Leases

The Company’s future minimum lease payments under operating leases that have noncancelable terms in excess of one year as of March 31, 2019 are as follows:




2020	$	31,483
2021	24,290
2022	16,514
2023	11,596
2024	8,683
Thereafter	23,757
Total minimum lease payments	$	116,323

Other Liabilities (Tables)

12 Months Ended

Mar. 31, 2019

Schedule Of Other Long-Term Liabilities

Other liabilities consist of the following:



	March 31,
	2019		2018
Tax Act - Transition Tax	$	55,489	$	89,700
Pension	39,924		44,404
Warranty	32,922		27,965
Liability for uncertain tax positions	20,240		1,684
Deferred income	—		7,094
Contract liabilities	6,360		—
Other	10,265		10,240
Total	$	165,200	$	181,087

Fair Value of Financial Instruments (Tables)

12 Months Ended

Mar. 31, 2019

Financial Assets And (Liabilities), Measured At Fair Value On A Recurring Basis

The following tables represent the financial assets and (liabilities) measured at fair value on a recurring basis as of March 31, 2019 and March 31, 2018 and the basis for that measurement:



	Total Fair Value Measurement March 31, 2019			Quoted Price in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Lead forward contracts	$	(902	)	$	—	$	(902	)	$	—
Foreign currency forward contracts	(249		)	—		(249		)	—
Total derivatives	$	(1,151	)	$	—	$	(1,151	)	$	—



	Total Fair Value Measurement March 31, 2018			Quoted Price in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Lead forward contracts	$	(3,877	)	$	—	$	(3,877	)	$	—
Foreign currency forward contracts	22			—		22			—
Total derivatives	$	(3,855	)	$	—	$	(3,855	)	$	—

Carrying Amounts And Estimated Fair Values Of Company's Financial Instruments

The carrying amounts and estimated fair values of the Company’s derivatives and Notes at March 31, 2019 and 2018 were as follows:



	March 31, 2019				March 31, 2018
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Financial assets:
Derivatives⁽¹⁾	$	—	$	—	$	22	$	22
Financial liabilities:
Notes ⁽²⁾	300,000		297,000		300,000		304,500
Derivatives⁽¹⁾	$	1,151	$	1,151	$	3,877	$	3,877


(1)	Represents lead and foreign currency forward contracts (see Note 12 for asset and liability positions of the lead and foreign currency forward contracts at March 31, 2019 and March 31, 2018).


(2)	The fair value amount of the Notes at March 31, 2019 and March 31, 2018 represent the trading value of the instruments.

Derivative Financial Instruments (Tables)

12 Months Ended

Mar. 31, 2019

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Fair Value Of Derivative Instruments In The Consolidated Balance Sheets

Fair Value of Derivative Instruments

March 31, 2019 and 2018



	Derivatives and Hedging Activities Designated as Cash Flow Hedges				Derivatives and Hedging Activities Not Designated as Hedging Instruments
	March 31, 2019		March 31, 2018		March 31, 2019		March 31, 2018
Prepaid and other current assets:
Foreign currency forward contracts	—		209		—		—
Total assets	$	—	$	209	$	—	$	—
Accrued expenses:
Lead forward contracts	$	902	$	3,877	$	—	$	—
Foreign currency forward contracts	8		—		241		187
Total liabilities	$	910	$	3,877	$	241	$	187

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ended March 31, 2017



Derivatives Designated as Cash Flow Hedges	Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)		Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Lead forward contracts	$	7,907	Cost of goods sold	$	5,803
Foreign currency forward contracts	845		Cost of goods sold	433
Total	$	8,752		$	6,236

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ended March 31, 2019



Derivatives Designated as Cash Flow Hedges	Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Lead forward contracts	$	(12,531	)	Cost of goods sold	$	(15,666	)
Foreign currency forward contracts	1,551			Cost of goods sold	385
Total	$	(10,980	)		$	(15,281	)

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ended March 31, 2018



Derivatives Designated as Cash Flow Hedges	Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Lead forward contracts	$	(805	)	Cost of goods sold	$	5,860
Foreign currency forward contracts	(3,524		)	Cost of goods sold	(2,718		)
Total	$	(4,329	)		$	3,142

Effect Of Derivative Instruments



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivatives	Pretax Gain (Loss)
Foreign currency forward contracts	Other (income) expense, net	$	180
Total		$	180



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivatives	Pretax Gain (Loss)
Foreign currency forward contracts	Other (income) expense, net	$	(1,856	)
Total		$	(1,856	)



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivatives	Pretax Gain (Loss)
Foreign currency forward contracts	Other (income) expense, net	$	(471	)
Total		$	(471	)

Income Taxes (Tables)

12 Months Ended

Mar. 31, 2019

Earnings Before Income Taxes

Income Tax Expense



	Fiscal year ended March 31,
	2019			2018			2017
Current income tax expense
Current:
Federal	$	6,377		$	115,315		$	30,362
State	5,027			3,461			4,855
Foreign	16,636			20,030			17,800
Total current income tax expense	28,040			138,806			53,017
Deferred income tax (benefit) expense
Federal	(5,031		)	(9,551		)	857
State	(669		)	789			590
Foreign	(756		)	(11,551		)	8
Total deferred income tax (benefit) expense	(6,456		)	(20,313		)	1,455
Total income tax expense	$	21,584		$	118,493		$	54,472

Earnings before income taxes consists of the following:



	Fiscal year ended March 31,
	2019		2018		2017
United States	$	53,339	$	74,440	$	80,436
Foreign	128,872		163,886		132,259
Earnings before income taxes	$	182,211	$	238,326	$	212,695

Deferred Tax Assets And Liabilities

The following table sets forth the tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities:



	March 31,
	2019			2018
Deferred tax assets:
Accounts receivable	$	1,297		$	1,790
Inventories	4,081			3,660
Net operating loss carryforwards	48,423			50,928
Accrued expenses	21,574			21,274
Capitalized research and development costs	7,061			—
Other assets	17,656			16,832
Gross deferred tax assets	100,092			94,484
Less valuation allowance	(17,519		)	(15,255		)
Total deferred tax assets	82,573			79,229
Deferred tax liabilities:
Property, plant and equipment	25,656			21,045
Intangible assets	96,826			46,058
Other liabilities	1,737			1,331
Total deferred tax liabilities	124,219			68,434
Net deferred tax (liabilities) assets	$	(41,646	)	$	10,795

Reconciliation Of Income Taxes At The Statutory Rate

A reconciliation of income taxes at the statutory rate (21.0% for fiscal 2019, 31.55% for fiscal 2018 and 35% for fiscal 2017) to the income tax provision is as follows:



	Fiscal year ended March 31,
	2019			2018			2017
United States statutory income tax expense	$	38,264		$	75,196		$	74,444
Increase (decrease) resulting from:
Impact of Tax Act	(13,483		)	83,400			—
State income taxes, net of federal effect	3,285			3,146			3,677
Nondeductible expenses, domestic manufacturing deduction (fiscal 2018 and 2017) and other	2,677			1,078			1,993
Legal proceedings charge - European Competition Investigations - See Note 18	2,405			—			7,873
Net effect of GILTI, FDII, BEAT	2,320			—			—
Goodwill impairment - See Note 5	—			—			3,812
Effect of foreign operations	(16,763		)	(35,048		)	(39,377		)
Valuation allowance	2,879			(9,279		)	2,050
Income tax expense	$	21,584		$	118,493		$	54,472

Reconciliation Of Unrecognized Tax Benefits



	Fiscal year ended March 31,
	2019			2018			2017
Balance at beginning of year	$	1,568		$	1,450		$	2,375
Increases related to current year tax positions	129			397			252
Increases related to the Alpha acquisition	7,840			—			—
Increases related to prior year tax positions	11,463			11			31
Decreases related to prior tax positions and foreign currency translation	(544		)	—			(352		)
Decreases related to prior year tax positions settled	(93		)	(1		)	(678		)
Lapse of statute of limitations	(198		)	(289		)	(178		)
Balance at end of year	$	20,165		$	1,568		$	1,450

Retirement Plans (Tables)

12 Months Ended

Mar. 31, 2019

Components Of Net Periodic Pension Cost

Net periodic pension cost for fiscal 2019, 2018 and 2017, includes the following components:



	United States Plans									International Plans
	Fiscal year ended March 31,									Fiscal year ended March 31,
	2019			2018			2017			2019			2018			2017
Service cost	$	—		$	—		$	371		$	997		$	1,025		$	871
Interest cost	631			658			664			1,831			1,795			1,848
Expected return on plan assets	(514		)	(496		)	(816		)	(2,151		)	(2,264		)	(1,875		)
Amortization and deferral	184			303			453			1,520			1,468			978
Net periodic benefit cost	$	301		$	465		$	672		$	2,197		$	2,024		$	1,822

Summary Of Change In Projected Benefit Obligation



	United States Plans						International Plans
	March 31,						March 31,
	2019			2018			2019			2018
Change in projected benefit obligation
Benefit obligation at the beginning of the period	$	16,713		$	16,682		$	82,033		$	74,478
Service cost	—			—			997			1,025
Interest cost	631			658			1,831			1,795
Benefits paid, inclusive of plan expenses	(1,061		)	(1,037		)	(1,758		)	(2,153		)
Plan curtailments and settlements	—			—			(1,130		)	(52		)
Actuarial losses (gains)	364			410			(261		)	(2,705		)
Foreign currency translation adjustment	—			—			(6,674		)	9,645
Benefit obligation at the end of the period	$	16,647		$	16,713		$	75,038		$	82,033

Summary Of Change In Plan Assets



Change in plan assets
Fair value of plan assets at the beginning of the period	$	13,928		$	12,731		$	38,757		$	34,323
Actual return on plan assets	758			1,731			2,109			688
Employer contributions	138			503			1,670			1,865
Benefits paid, inclusive of plan expenses	(1,061		)	(1,037		)	(1,758		)	(2,153		)
Plan curtailments and settlements	—			—			(1,130		)	(52		)
Foreign currency translation adjustment	—			—			(2,857		)	4,086
Fair value of plan assets at the end of the period	$	13,763		$	13,928		$	36,791		$	38,757
Funded status deficit	$	(2,884	)	$	(2,785	)	$	(38,247	)	$	(43,276	)

Summary Of Amounts Recognized In The Balance Sheets



	March 31,
	2019			2018
Amounts recognized in the Consolidated Balance Sheets consist of:
Accrued expenses	(1,207		)	(1,657		)
Other liabilities	(39,924		)	(44,404		)
Total liabilities	$	(41,131	)	$	(46,061	)

Summary Of Amounts In AOCI Before Taxes

The following table represents pension components (before tax) and related changes (before tax) recognized in AOCI for the Company’s pension plans for the years ended March 31, 2019, 2018 and 2017:



	Fiscal year ended March 31,
	2019			2018			2017
Amounts recorded in AOCI before taxes:
Prior service cost	$	(307	)	$	(385	)	$	(377	)
Net loss	(24,051		)	(27,762		)	(28,475		)
Net amount recognized	$	(24,358	)	$	(28,147	)	$	(28,852	)

Summary Of Changes In AOCI



	Fiscal year ended March 31,
	2019			2018			2017
Changes in plan assets and benefit obligations:
New prior service cost	$	—		$	—		$	—
Net loss (gain) arising during the year	(99		)	(1,953		)	5,485
Effect of exchange rates on amounts included in AOCI	(1,984		)	3,019			(2,275		)
Amounts recognized as a component of net periodic benefit costs:
Amortization of prior service cost	(45		)	(46		)	(42		)
Amortization or settlement recognition of net loss	(1,659		)	(1,725		)	(1,389		)
Total recognized in other comprehensive (income) loss	$	(3,787	)	$	(705	)	$	1,779

Summary Of Recognized Components Of Net Periodic Pension Cost Included In Accumulated Other Comprehensive Income

The amounts included in AOCI as of March 31, 2019 that are expected to be recognized as components of net periodic pension cost (before tax) during the next twelve months are as follows:



Prior service cost	$	(44	)
Net loss	(1,185		)
Net amount expected to be recognized	$	(1,229	)

Summary Of Accumulated Benefit Obligation Related To All Defined Pension Plans



	United States Plans				International Plans
	March 31,				March 31,
	2019		2018		2019		2018
All defined benefit plans:
Accumulated benefit obligation	$	16,647	$	16,713	$	71,350	$	77,724
Unfunded defined benefit plans:
Projected benefit obligation	$	—	$	—	$	32,320	$	33,124
Accumulated benefit obligation	—		—		30,328		31,270
Defined benefit plans with a projected benefit obligation in excess of the fair value of plan assets:
Projected benefit obligation	$	16,647	$	16,713	$	75,038	$	82,033
Fair value of plan assets	13,763		13,928		36,791		38,757
Defined benefit plans with an accumulated benefit obligation in excess of the fair value of plan assets:
Projected benefit obligation	$	16,647	$	16,713	$	74,235	$	81,253
Accumulated benefit obligation	16,647		16,713		70,654		77,021
Fair value of plan assets	13,763		13,928		36,077		37,986

Significant Assumptions Used To Determine The Net Periodic Benefit Cost

Significant assumptions used to determine the net periodic benefit cost for the U.S. and International plans were as follows:



	United States Plans						International Plans
	Fiscal year ended March 31,						Fiscal year ended March 31,
	2019		2018		2017		2019	2018	2017
Discount rate	3.9	%	4.1	%	3.9	%	1.4-3.3%	1.5-3.5%	1.8-3.7%
Expected return on plan assets	6.3		6.8		7.0		4.1-6.0	3.6-6.3	3.3-6.5
Rate of compensation increase	N/A		N/A		N/A		1.8-4.0	1.5-4.0	1.5-4.0

Significant Assumptions Used To Determine The Projected Benefit Obligations

Significant assumptions used to determine the projected benefit obligations for the U.S. and International plans were as follows:



	United States Plans				International Plans
	March 31,				March 31,
	2019		2018		2019	2018
Discount rate	3.8	%	3.9	%	1.0-2.7%	1.4-3.3%
Rate of compensation increase	N/A		N/A		2.0-4.0	1.8-4.0

Summary Of Pension Plan Investments Measured At Fair Value

The following table represents the Company's pension plan investments measured at fair value as of March 31, 2019 and 2018 and the basis for that measurement:



	March 31, 2019
	United States Plans								International Plans
	Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Asset category:
Cash and cash equivalents	$	1,080	$	1,080	$	—	$	—	$	83	$	83	$	—	$	—
Equity securities
US^(a)	8,275		8,275		—		—		—		—		—		—
International^(b)	—		—		—		—		23,875		—		23,875		—
Fixed income^(c)	4,408		4,408		—		—		12,833		—		12,833		—
Total	$	13,763	$	13,763	$	—	$	—	$	36,791	$	83	$	36,708	$	—



	March 31, 2018
	United States Plans								International Plans
	Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Asset category:
Cash and cash equivalents	$	891	$	891	$	—	$	—	$	49	$	49	$	—	$	—
Equity securities
US^(a)	9,864		9,864		—		—		—		—		—		—
International^(b)	—		—		—		—		25,768		—		25,768		—
Fixed income^(c)	3,173		3,173		—		—		12,940		—		12,940		—
Total	$	13,928	$	13,928	$	—	$	—	$	38,757	$	49	$	38,708	$	—

The fair values presented above were determined based on valuation techniques to measure fair value as discussed in Note 1.


(a)	US equities include companies that are well diversified by industry sector and equity style (i.e., growth and value strategies). Active and passive management strategies are employed. Investments are primarily in large capitalization stocks and, to a lesser extent, mid- and small-cap stocks.


(b)	International equities are invested in companies that are traded on exchanges outside the U.S. and are well diversified by industry sector, country and equity style. Active and passive strategies are employed. The vast majority of the investments are made in companies in developed markets with a small percentage in emerging markets.

(c)

Fixed income consists primarily of investment grade bonds from diversified industries.

Summary Of Estimated Future Benefit Payments

Estimated future benefit payments under the Company’s pension plans are as follows:




2020	$	2,713
2021	2,783
2022	3,072
2023	3,392
2024	3,536
Years 2025-2029	21,106

Stockholders' Equity and Noncontrolling Interests (Tables)

12 Months Ended

Mar. 31, 2019

Stockholders' Equity and Noncontrolling Interests [Abstract]

Change in Number of Shares of Common Stock Outstanding

The following summarizes the change in the number of shares of common stock outstanding during fiscal years ended March 31, 2017, 2018 and 2019, respectively:




Shares outstanding as of March 31, 2016	43,189,502
Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes	258,034
Shares outstanding as of March 31, 2017	43,447,536
Purchase of treasury stock	(1,756,831	)
Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes	224,295
Shares outstanding as of March 31, 2018	41,915,000
Purchase of treasury stock	(726,347	)
Shares issued towards purchase consideration of Alpha acquisition	1,177,630
Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes	254,467
Shares outstanding as of March 31, 2019	42,620,750

Components Of Accumulated Other Comprehensive Income

The components of AOCI, net of tax, are as follows:



	Beginning Balance			Before Reclassifications			Amount Reclassified from AOCI			Ending Balance
March 31, 2019
Pension funded status adjustment	$	(22,503	)	$	339		$	1,373		$	(20,791	)
Net unrealized gain (loss) on derivative instruments	(3,425		)	(8,396		)	11,691			(130		)
Foreign currency translation adjustment	(15,789		)	(105,972		)	—			(121,761		)
Accumulated other comprehensive loss	$	(41,717	)	$	(114,029	)	$	13,064		$	(142,682	)
March 31, 2018
Pension funded status adjustment	$	(25,555	)	$	1,692		$	1,360		$	(22,503	)
Net unrealized gain (loss) on derivative instruments	1,975			(2,868		)	(2,532		)	(3,425		)
Foreign currency translation adjustment	(129,244		)	113,455			—			(15,789		)
Accumulated other comprehensive loss	$	(152,824	)	$	112,279		$	(1,172	)	$	(41,717	)
March 31, 2017
Pension funded status adjustment	$	(21,861	)	$	(4,659	)	$	965		$	(25,555	)
Net unrealized gain (loss) on derivative instruments	388			5,523			(3,936		)	1,975
Foreign currency translation adjustment	(75,876		)	(53,368		)	—			(129,244		)
Accumulated other comprehensive loss	$	(97,349	)	$	(52,504	)	$	(2,971	)	$	(152,824	)

Reclassification out of Accumulated Other Comprehensive Income

The following table presents reclassifications from AOCI during the twelve months ended March 31, 2019:



Components of AOCI	Amounts Reclassified from AOCI			Location of (Gain) Loss Recognized on Income Statement
Derivatives in Cash Flow Hedging Relationships:
Net unrealized loss on derivative instruments	$	15,281		Cost of goods sold
Tax benefit	(3,590		)
Net unrealized loss on derivative instruments, net of tax	$	11,691

Defined benefit pension costs:
Prior service costs and deferrals	$	1,704		Net periodic benefit cost, included in other (income) expense, net - See Note 1 and 14
Tax benefit	(331		)
Net periodic benefit cost, net of tax	$	1,373

Summary of Redeemable Noncontrolling Interests

The following demonstrates the change in redeemable noncontrolling interests during the fiscal year ended March 31, 2017:




Balance as of March 31, 2016	$	5,997
Net losses attributable to redeemable noncontrolling interests	(2,021		)
Deconsolidation of joint venture	(4,035		)
Foreign currency translation adjustment	59
Balance as of March 31, 2017	$	—

Stock-Based Compensation (Tables)

12 Months Ended

Mar. 31, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary Of Stock Option Activity

The following table summarizes the Company’s stock option activity in the years indicated:



	Number of Options		Weighted- Average Remaining Contract Term (Years)	Weighted- Average Exercise Price		Aggregate Intrinsic Value
Options outstanding as of March 31, 2016	210,297		8.5	$	67.54	$	218
Granted	242,068			57.60		—
Exercised	(263	)		18.25		12
Expired	(434	)		18.25		15
Options outstanding as of March 31, 2017	451,668		8.4	$	62.29	$	7,520
Granted	169,703			83.14		—
Exercised	(62,197	)		63.44		1,132
Forfeited	(11,495	)		70.22		75
Expired	(2,089	)		18.25		137
Options outstanding as of March 31, 2018	545,590		8.4	$	68.65	$	2,679
Granted	192,700			75.17		—
Exercised	(171,630	)		63.66		2,707
Forfeited	(11,754	)		75.17		—
Options outstanding as of March 31, 2019	554,906		8.0	$	72.31	$	1,040
Options exercisable as of March 31, 2019	186,823		6.9	$	69.34	$	452
Options vested and expected to vest, as of March 31, 2019	545,299		8.0	$	72.24	$	1,038

Summary Of Information Regarding Stock Options Outstanding And Exercisable

The following table summarizes information regarding stock options outstanding as of March 31, 2019:




Range of Exercise Prices	Number of Options	Weighted- Average Remaining Contractual Life (Years)	Weighted- Average Exercise Price
$55.00-$60.00	137,599	7.1	$	57.60
$65.01-$70.00	73,368	5.8	$	68.82
$75.01-$83.14	343,939	8.8	$	78.95
	554,906	8.0	$	72.31

Summary Of The Changes In Restricted Stock Units And Market Share Units



	Restricted Stock Units (RSU)				Market condition-based Share Units (TSR)				Performance condition-based Share Units (PSU)
	Number of RSU		Weighted- Average Grant Date Fair Value		Number of TSR		Weighted- Average Grant Date Fair Value		Number of PSU		Weighted- Average Grant Date
Non-vested awards as of March 31, 2018	633,751		$	56.60	349,941		$	70.22	—		$	—
Granted	241,105		69.43		36,646		85.84		45,883		68.48
Stock dividend	6,087		56.81		3,131		72.60		320		68.48
Performance factor	—		—		143		75.48		—		—
Vested	(148,487	)	68.55		(3,482	)	59.94		—		—
Canceled	(10,809	)	72.56		(33,795	)	62.21		(3,677	)	68.48
Non-vested awards as of March 31, 2019	721,647		$	57.72	352,584		$	72.83	42,526		$	68.48

Earnings Per Share (Tables)

12 Months Ended

Mar. 31, 2018

Reconciliation From Basic To Diluted Average Common Shares And Net Earnings Per Common Share



	Fiscal year ended March 31,
	2019		2018		2017
Net earnings attributable to EnerSys stockholders	$	160,239	$	119,594	$	160,214
Weighted-average number of common shares outstanding:
Basic	42,335,023		42,612,036		43,389,333
Dilutive effect of:
Common shares from exercise and lapse of equity awards, net of shares assumed reacquired	673,929		507,820		623,210
Diluted weighted-average number of common shares outstanding	43,008,952		43,119,856		44,012,543
Basic earnings per common share attributable to EnerSys stockholders	$	3.79	$	2.81	$	3.69
Diluted earnings per common share attributable to EnerSys stockholders	$	3.73	$	2.77	$	3.64
Anti-dilutive equity awards not included in diluted weighted-average common shares	355,728		59,482		1,295

Restructuring Plans and Other Exit Charges (Tables)

12 Months Ended

Mar. 31, 2019

Restructuring and Related Activities [Abstract]

Acquisition And Non-Acquisition Related Restructuring Reserve

A roll-forward of the restructuring reserve is as follows:



	Employee Severance			Other			Total
Balance at March 31, 2016	$	2,964		$	25		$	2,989
Accrued	4,566			742			5,308
Costs incurred	(4,754		)	(604		)	(5,358		)
Foreign currency impact and other	(108		)	(19		)	(127		)
Balance at March 31, 2017	$	2,668		$	144		$	2,812
Accrued	4,757			445			5,202
Costs incurred	(4,849		)	(574		)	(5,423		)
Foreign currency impact and other	317			1			318
Balance at March 31, 2018	$	2,893		$	16		$	2,909
Accrued	6,554			1,639			8,193
Costs incurred	(6,893		)	(1,086		)	(7,979		)
Foreign currency impact and other	(198		)	27			(171		)
Balance at March 31, 2019	$	2,356		$	596		$	2,952

Warranty (Tables)

12 Months Ended

Mar. 31, 2019

Analysis Of Changes In Liability For Product Warranties



	Fiscal year ended March 31,
	2019			2018			2017
Balance at beginning of year	$	50,602		$	46,116		$	48,422
Current year provisions	23,679			21,706			17,852
Costs incurred	(25,053		)	(18,820		)	(15,945		)
Warranty reserves of acquired business - Alpha	7,535			—			—
Foreign currency translation adjustment	(2,195		)	1,600			(4,213		)
Balance at end of year	$	54,568		$	50,602		$	46,116

Other (Income) Expense, Net (Tables)

12 Months Ended

Mar. 31, 2019

Summary Of Other (Income) Expense, Net

Other (income) expense, net consists of the following:



	Fiscal year ended March 31,
	2019			2018		2017
Foreign exchange transaction (gains) losses	$	(3,044	)	$	5,499	$	(662	)
Non-service components of pension expense	1,502			1,464		1,252
Other	928			556		1,631
Total	$	(614	)	$	7,519	$	2,221

Business Segments (Tables)

12 Months Ended

Mar. 31, 2019

Summary Of Financial Information Related To The Company's Business Segments

Summarized financial information related to the Company’s reportable segments at March 31, 2019, 2018 and 2017 and for each of the fiscal years then ended is shown below.



	Fiscal year ended March 31,
	2019			2018			2017
Net sales by segment to unaffiliated customers
Americas	$	1,690,912		$	1,429,888		$	1,332,353
EMEA	860,563			849,420			763,013
Asia	256,542			302,583			271,783
Total net sales	$	2,808,017		$	2,581,891		$	2,367,149
Net sales by product line
Reserve power	$	1,416,173		$	1,247,900		$	1,142,327
Motive power	1,391,844			1,333,991			1,224,822
Total net sales	$	2,808,017		$	2,581,891		$	2,367,149
Intersegment sales
Americas	$	28,753		$	29,513		$	26,039
EMEA	123,274			133,164			93,150
Asia	34,531			23,375			22,584
Total intersegment sales⁽¹⁾	$	186,558		$	186,052		$	141,773
Operating earnings by segment
Americas	$	186,814		$	189,466		$	191,801
EMEA	71,963			77,671			77,376
Asia	3,213			12,647			14,994
Inventory step up to fair value relating to acquisition - Americas	(7,263		)	—			—
Inventory adjustment relating to exit activities - Americas	—			(3,457		)	—
Inventory adjustment relating to exit activities - EMEA	(2,590		)	—			(2,157		)
Inventory adjustment relating to exit activities - Asia	(526		)	—			—
Restructuring charges - Americas	(4,066		)	(1,246		)	(892		)
Restructuring and other exit charges - EMEA	(26,989		)	(4,023		)	(5,487		)
Restructuring charges - Asia	(3,654		)	(212		)	(781		)
Impairment of goodwill and indefinite-lived intangibles - Americas	—			—			(9,346		)
Impairment of goodwill and indefinite-lived intangibles - EMEA	—			—			(4,670		)
Legal proceedings charge, net - EMEA	(4,437		)	—			(23,725		)
Total operating earnings⁽²⁾	$	212,465		$	270,846		$	237,113
Property, plant and equipment, net
Americas	$	257,559		$	210,998		$	190,169
EMEA	94,932			118,263			100,042
Asia	56,948			60,999			58,338
Total	$	409,439		$	390,260		$	348,549
Capital Expenditures
Americas	$	45,029		$	46,905		$	34,809
EMEA	18,972			18,392			13,733
Asia	6,371			4,535			1,530
Total	$	70,372		$	69,832		$	50,072
Depreciation and Amortization
Americas	$	40,675		$	30,421		$	30,204
EMEA	15,128			16,198			15,693
Asia	7,545			7,698			8,048
Total	$	63,348		$	54,317		$	53,945


(1)	Intersegment sales are presented on a cost-plus basis which takes into consideration the effect of transfer prices between legal entities.

(2)

The Company does not allocate interest expense or other (income) expense, net, to the reportable segments.

Quarterly Financial Data (Tables)

12 Months Ended

Mar. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Summary Of Interim Financial Information



	1st Quarter		2nd Quarter		3rd Quarter			4th Quarter		Fiscal Year
Fiscal year ended March 31, 2019
Net sales	$	670,930	$	660,462	$	680,022		$	796,603	$	2,808,017
Gross profit	165,334		160,880		164,546			202,266		693,026
Operating earnings^(1)(3)(5)	64,179		63,357		49,951			34,978		212,465
Net earnings⁽⁶⁾	46,020		47,447		48,614			18,546		160,627
Net earnings attributable to EnerSys stockholders	45,860		47,424		48,417			18,538		160,239
Net earnings per common share attributable to EnerSys stockholders—basic	$	1.09	$	1.13	$	1.14		$	0.43	$	3.79
Net earnings per common share attributable to EnerSys stockholders—diluted	$	1.08	$	1.11	$	1.12		$	0.42	$	3.73
Fiscal year ended March 31, 2018
Net sales	$	622,625	$	617,289	$	658,935		$	683,042	$	2,581,891
Gross profit	163,458		160,248		167,310			167,388		658,404
Operating earnings⁽²⁾⁽⁴⁾	69,972		64,364		68,785			67,725		270,846
Net earnings (loss)⁽⁷⁾	48,322		43,151		(25,779		)	54,139		119,833
Net earnings (loss) attributable to EnerSys stockholders	48,201		43,222		(25,847		)	54,018		119,594
Net earnings (loss) per common share attributable to EnerSys stockholders—basic	$	1.11	$	1.01	$	(0.61	)	$	1.29	$	2.81
Net earnings (loss) per common share attributable to EnerSys stockholders—diluted	$	1.09	$	1.00	$	(0.61	)	$	1.27	$	2.77


(1)	Included in Operating earnings were inventory adjustment relating to exit activities of $526 and $2,590 in the first and fourth quarter of fiscal 2019, respectively. Also included were inventory adjustments relating to Alpha acquisition of $3,747 and $3,516 in the third and fourth quarter of fiscal 2019, respectively.


(2)	Included in Operating earnings were inventory adjustment relating to exit activities of $3,457 in the fourth quarter of fiscal 2018, respectively.


(3)	Included in Operating earnings were restructuring and other exit charges of $1,739, $1,121, $5,392 and $26,457 for the first, second, third and fourth quarters of fiscal 2019, respectively.


(4)	Included in Operating earnings were restructuring and other exit charges of $833, $1,776, $1,808 and $1,064 for the first, second, third and fourth quarters of fiscal 2018, respectively.


(5)	Included in Operating earnings were legal proceedings settlement income of $2,843 in the third quarter and expense of $7,280 in the fourth quarter of fiscal 2019.


(6)	Included in net earnings was a tax benefit of $13,483 for the third quarter of fiscal 2019, on account of the Tax Act.

(7)

Included in net earnings (loss) was tax expense of $77,347 and $4,106 for the third and fourth quarters of fiscal 2018, respectively, on account of the Tax Act.

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended								12 Months Ended
	Mar. 31, 2019 USD ($)	Dec. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jul. 01, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Oct. 01, 2017 USD ($)	Jul. 02, 2017 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($) segment shares	Mar. 31, 2017 USD ($)	Apr. 01, 2019 USD ($)	Apr. 01, 2018 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents include all highly liquid investments with an original maturity, when purchased, in months										3 months
Number of geographical regions \| segment										3
Reclassification of goodwill impairment									$ 0	$ 0	$ 12,216,000
Revenue	$ 796,603,000	$ 680,022,000	$ 660,462,000	$ 670,930,000	$ 683,042,000	$ 658,935,000	$ 617,289,000	$ 622,625,000	2,808,017,000	2,581,891,000	$ 2,367,149,000
Revenue recognized									6,132,000
Contract liability, current	15,162,000								15,162,000
Contract liability, noncurrent	6,360,000								6,360,000
Contract assets	38,778,000				$ 0				38,778,000	$ 0
Anticipated value of right of return assets	2,667,000								2,667,000
Refund liability	$ 5,153,000								5,153,000
Restricted Stock and Restricted Stock Units
Summary Of Significant Accounting Policies [Line Items]
Percentage of restricted stock units granted, vested per year										25.00%
Vesting period, in years										4 years
Services
Summary Of Significant Accounting Policies [Line Items]
Revenue									$ 157,236,000
Minimum
Summary Of Significant Accounting Policies [Line Items]
Percentage of investment ownership, consolidated	50.00%								50.00%
Percentage of investment ownership, equity method	20.00%								20.00%
Estimated useful lives of finite-lived assets										3 years
Market share units converted into common stock for each unit \| shares										0
Minimum \| Reserve Power Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period										1 year
Minimum \| Motive Power Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period										1 year
Minimum \| Building and Improvements
Summary Of Significant Accounting Policies [Line Items]
Property, plant, and equipment, useful life										10 years
Minimum \| Machinery and Equipment
Summary Of Significant Accounting Policies [Line Items]
Property, plant, and equipment, useful life										3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Percentage of investment ownership, equity method	50.00%								50.00%
Percentage of investment ownership, cost method	20.00%								20.00%
Estimated useful lives of finite-lived assets										20 years
Market share units converted into common stock for each unit \| shares										2
Maximum \| Reserve Power Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period										20 years
Maximum \| Motive Power Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period										7 years
Maximum \| Building and Improvements
Summary Of Significant Accounting Policies [Line Items]
Property, plant, and equipment, useful life										33 years
Maximum \| Machinery and Equipment
Summary Of Significant Accounting Policies [Line Items]
Property, plant, and equipment, useful life										15 years
Transferred over Time
Summary Of Significant Accounting Policies [Line Items]
Revenue recognized									$ 100,809,000
Accounting Standards Update 2016-02 [Member] \| Scenario, Forecast [Member]
Summary Of Significant Accounting Policies [Line Items]
Expected lease liability to be recognized												$ 100,000,000
Difference between Revenue Guidance in Effect before and after Topic 606 \| Accounting Standards Update 2014-09
Summary Of Significant Accounting Policies [Line Items]
Contract liability, current													$ 9,387,000
Contract liability, noncurrent													7,094,000
Contract assets													$ 24,810,000

Summary of Significant Accounting Policies - Remaining Performance Obligation (Detail) $ in Thousands	Mar. 31, 2019 USD ($)
Accounting Policies [Abstract]
Remaining performance obligation	$ 66,088
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-04-01
Accounting Policies [Abstract]
Remaining performance obligation	$ 60,443
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Accounting Policies [Abstract]
Remaining performance obligation	$ 5,645
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year

Acquisitions - Additional Information (Detail)		9 Months Ended	12 Months Ended
Acquisitions - Additional Information (Detail)	Dec. 07, 2018 USD ($) $ / shares shares	Dec. 30, 2018 USD ($)	Mar. 31, 2019 USD ($) shares	Mar. 31, 2018 USD ($) acquisition	Mar. 31, 2017 USD ($) acquisition
Business Acquisition [Line Items]
Number of businesses acquired \| acquisition				0	0
Purchase of businesses			$ 654,614,000	$ 2,988,000	$ 12,392,000
Goodwill relating to acquisitions			320,618,000	3,670,000
Estimated tax-deductible goodwill			$ 58,699,000	$ 18,147,000
Shares issued in acquisition (in shares) \| shares			1,177,630
Closing day spot rate (USD per share) \| $ / shares	$ 79.20
Alpha
Business Acquisition [Line Items]
Initial purchase consideration	$ 750,000,000
Consideration transferred	742,502,000
Acquisition cost expensed			$ 12,883,000
Estimated tax-deductible goodwill			42,262,000
Inventory adjustment			7,263,000
Payments to acquire businesses	650,000,000
Shares issued in acquisition, value	93,268,000
Working capital adjustment	$ 766,000
Shares issued in acquisition (USD per share) \| $ / shares	$ 84.92
Revenues and gains recognized in acquisition			162,454,000
Expenses and losses recognized in acquisition			1,252,000
Alpha \| Customer relationships
Business Acquisition [Line Items]
Acquired intangible assets	$ 221,000,000
Minimum
Business Acquisition [Line Items]
Estimated useful lives of finite-lived assets				3 years
Maximum
Business Acquisition [Line Items]
Consideration transferred		$ 250,000,000
Estimated useful lives of finite-lived assets				20 years
Trademarks \| Alpha
Business Acquisition [Line Items]
Acquired indefinite-lived intangible assets	$ 56,000,000
Common Stock \| Alpha
Business Acquisition [Line Items]
Shares issued in acquisition (in shares) \| shares	1,177,630
Operating Expense \| Alpha
Business Acquisition [Line Items]
Acquisition cost expensed			$ 12,883,000

Acquisitions Acquisitions - Assets and Liabilities Acquired (Details) - USD ($) $ in Thousands	Dec. 07, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Business Acquisition [Line Items]
Goodwill		$ 656,399	$ 352,805	$ 328,657
Alpha
Business Acquisition [Line Items]
Accounts receivable	$ 115,467
Inventories	84,297
Other current assets	6,822
Other intangible assets	332,000
Property, plant and equipment	20,987
Other assets	9,005
Total assets acquired	568,578
Accounts payable	35,803
Accrued liabilities	41,918
Deferred income taxes	56,331
Other liabilities	12,642
Total liabilities assumed	146,694
Net assets acquired	421,884
Cash paid for net assets acquired	650,000
Shares issued in acquisition, value	93,268
Working capital adjustment	(766)
Consideration transferred	742,502
Goodwill	$ 320,618

Acquisitions - Summary of Intangible Assets (Details) - Alpha $ in Thousands	Dec. 07, 2018 USD ($)
Business Acquisition [Line Items]
Other intangible assets	$ 332,000
Customer relationships
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	14 years
Acquired intangible assets	$ 221,000
Technology
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Acquired intangible assets	$ 55,000
Trademarks
Business Acquisition [Line Items]
Acquired indefinite-lived intangible assets	$ 56,000

Acquisitions - Pro Forma Information (Details) - Alpha - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition [Line Items]
Net sales	$ 3,278,646	$ 3,124,527
Net earnings attributable to EnerSys stockholders	$ 207,904	$ 126,965
Net earnings per share attributable to EnerSys stockholders - basic	$ 4,790	$ 2,900
Net earnings per share attributable to EnerSys stockholders - assuming dilution	$ 4,710	$ 2,870

Inventories - Summary of Inventories (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 138,718	$ 92,216
Work-in-process	129,736	136,068
Finished goods	235,415	185,950
Total	$ 503,869	$ 414,234

Property, Plant, and Equipment - Summary of PPE (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Property, Plant and Equipment [Abstract]
Land, buildings, and improvements	$ 268,006	$ 273,506
Machinery and equipment	683,955	657,262
Construction in progress	54,278	49,900
Property, Plant and Equipment, Gross, Total	1,006,239	980,668
Less accumulated depreciation	(596,800)	(590,408)
Total	$ 409,439	$ 390,260	$ 348,549

Property, Plant, and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 48,618	$ 45,874	$ 45,388
Interest capitalized	$ 1,581	$ 1,082	$ 817

Goodwill and Other Intangible Assets - Schedule of Companys Other Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Intangible Assets [Line Items]
Gross Amount, Total	$ 523,432	$ 193,532
Accumulated Amortization ,Total	(61,116)	(46,391)
Net Amount ,Total	462,316	147,141
Trademarks
Intangible Assets [Line Items]
Indefinite-lived intangible assets, Gross Amount	152,484	97,444
Finite-lived intangible assets, Gross Amount	2,003	2,003
Indefinite-lived intangible assets, Accumulated Amortization	(953)	(953)
Finite-lived intangible assets, Accumulated Amortization	(1,236)	(1,151)
Indefinite-lived intangible assets, Net Amount	151,531	96,491
Finite-lived intangible assets, Net Amount	767	852
Customer relationships
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	286,664	66,973
Finite-lived intangible assets, Accumulated Amortization	(42,704)	(31,500)
Finite-lived intangible assets, Net Amount	243,960	35,473
Noncompete Agreements
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	3,025	2,852
Finite-lived intangible assets, Accumulated Amortization	(2,807)	(2,759)
Finite-lived intangible assets, Net Amount	218	93
Patents
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	77,779	22,769
Finite-lived intangible assets, Accumulated Amortization	(12,229)	(8,872)
Finite-lived intangible assets, Net Amount	65,550	13,897
Licenses
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	1,477	1,491
Finite-lived intangible assets, Accumulated Amortization	(1,187)	(1,156)
Finite-lived intangible assets, Net Amount	$ 290	$ 335

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Mar. 05, 2019	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value		$ 725,576	$ 421,982
Amortization expense, related to finite-lived intangible assets		14,730	8,443	$ 8,557
Expected amortization expense, 2018		29,491
Expected amortization expense, 2019		29,237
Expected amortization expense, 2020		28,993
Expected amortization expense, 2021		27,694
Expected amortization expense, 2022		24,287
Impairment of goodwill		0	0	12,216
Asset impairment charges	$ 14,958
Estimated tax-deductible goodwill		58,699	18,147
Americas
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value		528,039	209,100
Impairment of goodwill				8,646
Impairment of indefinite-lived intangible assets				700
EMEA
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value		$ 149,422	$ 161,978
Impairment of goodwill				3,570
Impairment of indefinite-lived intangible assets				$ 1,100

Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill by Business Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Goodwill [Roll Forward]
Balance at beginning of year	$ 352,805	$ 328,657
Acquisitions during the year	320,618	3,670
Foreign currency translation adjustment	(17,024)	20,478
Balance at end of year	656,399	352,805
Americas
Goodwill [Roll Forward]
Balance at beginning of year	151,255	146,982
Acquisitions during the year	320,618	3,670
Foreign currency translation adjustment	(1,679)	603
Balance at end of year	470,194	151,255
EMEA
Goodwill [Roll Forward]
Balance at beginning of year	155,825	138,813
Acquisitions during the year	0	0
Foreign currency translation adjustment	(12,556)	17,012
Balance at end of year	143,269	155,825
Asia
Goodwill [Roll Forward]
Balance at beginning of year	45,725	42,862
Acquisitions during the year	0	0
Foreign currency translation adjustment	(2,789)	2,863
Balance at end of year	$ 42,936	$ 45,725

Goodwill and Other Intangible Assets - Schedule of Goodwill and Goodwill Impairment Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Goodwill [Line Items]
Gross carrying value	$ 725,576	$ 421,982
Accumulated goodwill impairment charges	(69,177)	(69,177)
Net book value	656,399	352,805	$ 328,657
Americas
Goodwill [Line Items]
Gross carrying value	528,039	209,100
Accumulated goodwill impairment charges	(57,845)	(57,845)
Net book value	470,194	151,255	146,982
EMEA
Goodwill [Line Items]
Gross carrying value	149,422	161,978
Accumulated goodwill impairment charges	(6,153)	(6,153)
Net book value	143,269	155,825	138,813
Asia
Goodwill [Line Items]
Gross carrying value	48,115	50,904
Accumulated goodwill impairment charges	(5,179)	(5,179)
Net book value	$ 42,936	$ 45,725	$ 42,862

Prepaid and Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Contract assets	$ 38,778	$ 0
Prepaid income taxes	9,608	8,921
Other	27,732	21,319
Total	$ 109,431	$ 56,910

Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Payables and Accruals [Abstract]
Payroll and benefits	$ 54,285	$ 50,053
Accrued selling expenses	35,394	34,831
Warranty	21,646	22,637
Project related accruals	16,301	0
Contract liabilities	15,162	0
Income taxes payable	9,234	19,696
Tax Act - Transition Tax	5,290	7,800
Restructuring	2,952	2,909
Pension	1,207	1,657
Other	48,356	27,095
Total	$ 255,881	$ 214,118

Debt - Long Term Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018	Dec. 27, 2015
Debt Instrument [Line Items]
Unamortized Debt Issuance Expense	$ (5,559)	$ (5,965)
Debt and Capital Lease Obligations	977,315	585,500
Long-term Debt and Capital Lease Obligations, Current	0	0
Long-term Debt and Capital Lease Obligations	971,756	579,535
Senior Unsecured 5.00% Due 2028
Debt Instrument [Line Items]
Long-term debt	300,000	300,000	$ 300,000
Unamortized Debt Issuance Expense	(2,497)	(3,122)
Incremental Commitment Agreement [Member] \| Secured Debt [Member] \| 2017 Revolver borrowings
Debt Instrument [Line Items]
Line of Credit Facility, Incremental Term Loan Commitment	677,315	285,500
Unamortized Debt Issuance Expense	$ (3,062)	$ (2,843)

Debt - Long Term Debt (Phantom) (Detail)	12 Months Ended
Debt - Long Term Debt (Phantom) (Detail)	Mar. 31, 2019
Senior Unsecured 3.375% Convertible Notes Due 2038
Debt Instrument [Line Items]
Interest rate of debt instrument	3.375%
Maturity year	2038
2011 Credit Facility Due 2018
Debt Instrument [Line Items]
Maturity year	2018

Debt - Additional Information (Detail)			9 Months Ended	12 Months Ended
Debt - Additional Information (Detail)	Aug. 04, 2017 USD ($)	Jul. 08, 2014	Dec. 30, 2018 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Dec. 07, 2018 USD ($)	Dec. 07, 2018 CAD ($)	Sep. 30, 2018	Aug. 03, 2017 USD ($)	Apr. 23, 2015 USD ($)
Debt Instrument [Line Items]
Line of Credit Facility, Increase in Borrowing Capacity Limit	$ 325,000,000
Company owned capital stock percentage	65.00%
Long-term Debt and Capital Lease Obligations, Current				$ 0	$ 0
Long-term Debt, Weighted Average Interest Rate, at Point in Time				4.10%	3.70%
Short term borrowing outstanding amount				$ 54,490,000	$ 18,341,000
Short-term debt, weighted-average interest rates				4.00%
Payments of Debt Issuance Costs				$ 1,393,000	2,677,000
Write off of Deferred Debt Issuance Cost				483,000	301,000
Deferred financing fees, net of accumulated amortization				5,559,000	5,965,000
Amortization expense included in interest expense				$ 1,316,000	1,302,000	$ 1,388,000
2011 Credit Facility Due 2018
Debt Instrument [Line Items]
Debt instrument maturity year				2018
Convertible Notes Payable
Debt Instrument [Line Items]
Available lines of credit				$ 546,960,000	613,234,000
Stand by letters of credit				3,955,000	3,074,000
Line of Credit Facility, Remaining Borrowing Capacity, Uncommitted Portion				$ 87,685,000	150,459,000
Senior Unsecured 5.00% Due 2023
Debt Instrument [Line Items]
Long-term debt											$ 300,000,000
Interest rate of debt instrument											5.00%
Senior Unsecured 3.375% Convertible Notes Due 2038
Debt Instrument [Line Items]
Interest rate of debt instrument				3.375%
Debt instrument maturity year				2038
Interest paid				$ 29,552,000	$ 23,527,000	$ 20,781,000
Maximum
Debt Instrument [Line Items]
Consideration transferred			$ 250,000,000
Amended 2017 Term Loan \| Term Loam [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity							$ 99,105,000	$ 133,050,000
Amended 2017 Term Loan \| Secured Debt [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity							449,105,000
Amended 2017 Revolver [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity							700,000,000
2017 Revolver borrowings \| Secured Debt [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity							299,105,000
Face value of debt instrument	$ 150,000,000
Available lines of credit				438,315,000
2017 Revolver borrowings \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	600,000,000						$ 100,000,000
Available lines of credit				239,000,000
Long-term Debt and Capital Lease Obligations, Current				$ 28,098,000
2011 Credit Facility Due 2018 \| Secured Debt [Member]
Debt Instrument [Line Items]
Face value of debt instrument										$ 150,000,000
Available lines of credit	123,750,000
2011 Credit Facility Due 2018 \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity										$ 500,000,000
Available lines of credit	240,000,000
Debt Instrument Quarterly Installments Beginning December 31, 2018 Through December 30, 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment	5,625,000
Debt Instrument Quarterly Installments Beginning December 31, 2019 Through December 30, 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment	8,438,000
Debt Instrument Quarterly Installments Beginning December 31, 2020 Through September 29, 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment	11,250,000
Debt Instrument Final Installments Payable On September 30, 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment	$ 315,000,000
London Interbank Offered Rate (LIBOR) [Member] \| 2017 Revolver And 2017 Term Loan [Member]
Debt Instrument [Line Items]
Interest at a floating rate	1.25%
London Interbank Offered Rate (LIBOR) [Member] \| 2017 Revolver And 2017 Term Loan [Member] \| Minimum
Debt Instrument [Line Items]
Interest at a floating rate	1.25%
London Interbank Offered Rate (LIBOR) [Member] \| 2017 Revolver And 2017 Term Loan [Member] \| Maximum
Debt Instrument [Line Items]
Interest at a floating rate	2.00%
London Interbank Offered Rate (LIBOR) [Member] \| Incremental Commitment Agreement [Member] \| Revolving Commitments and/or Term Loans [Member]
Debt Instrument [Line Items]
Interest at a floating rate						1.25%
London Interbank Offered Rate (LIBOR) [Member] \| Incremental Commitment Agreement [Member] \| Revolving Commitments and/or Term Loans [Member] \| Minimum
Debt Instrument [Line Items]
Interest at a floating rate		1.25%
London Interbank Offered Rate (LIBOR) [Member] \| Incremental Commitment Agreement [Member] \| Revolving Commitments and/or Term Loans [Member] \| Maximum
Debt Instrument [Line Items]
Interest at a floating rate		1.75%
Higher of Bank of America Prime Rate or Federal Funds Effective Rate [Member] \| Incremental Commitment Agreement [Member] \| Revolving Commitments and/or Term Loans [Member] \| Minimum
Debt Instrument [Line Items]
Interest at a floating rate		0.25%
Higher of Bank of America Prime Rate or Federal Funds Effective Rate [Member] \| Incremental Commitment Agreement [Member] \| Revolving Commitments and/or Term Loans [Member] \| Maximum
Debt Instrument [Line Items]
Interest at a floating rate		0.75%
Federal Funds Effective Swap Rate [Member] \| 2017 Revolver And 2017 Term Loan [Member]
Debt Instrument [Line Items]
Interest at a floating rate	0.50%
Eurodollar [Member] \| 2017 Revolver And 2017 Term Loan [Member]
Debt Instrument [Line Items]
Interest at a floating rate	1.00%
CDOR Rate [Member] \| 2017 Revolver And 2017 Term Loan [Member]
Debt Instrument [Line Items]
Interest at a floating rate	0.50%
Measurement Input, Maximum Leverage Ratio [Member]
Debt Instrument [Line Items]
Debt Instrument, Measurement Input			4.00						3.50

Leases - Schedule of Capital and Operating Leases (Detail) $ in Thousands	Mar. 31, 2019 USD ($)
Operating Leases
2019	$ 31,483
2020	24,290
2021	16,514
2022	11,596
2023	8,683
Thereafter	23,757
Total minimum lease payments	$ 116,323

Leases - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Leases [Abstract]
Rental expense	$ 40,261	$ 38,146	$ 35,991

Other Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Other Liabilities Disclosure [Abstract]
Tax Act - Transition Tax	$ 55,489	$ 89,700
Pension	39,924	44,404
Warranty	32,922	27,965
Contract liabilities	0	7,094
Contract liabilities	6,360	0
Other	10,265	10,240
Total	$ 165,200	$ 181,087

Fair Value of Financial Instruments - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	$ (1,151)	$ (3,855)
Lead hedge forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(902)	(3,877)
Foreign currency forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(249)	22
Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(1,151)	(3,855)
Significant Other Observable Inputs (Level 2) \| Lead hedge forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(902)	(3,877)
Significant Other Observable Inputs (Level 2) \| Foreign currency forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	$ (249)	$ 22

Fair Value of Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 05, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 27, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading of convertible notes, face value, disclosed as a percentage		99.00%	102.00%
Fixed asset impairment	$ 14,958
Senior Unsecured 5.00% Due 2028
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt		$ 300,000	$ 300,000	$ 300,000
Fair Value, Measurements, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of fixed assets		$ 242

Fair Value of Financial Instruments - Carrying Amounts and Estimated Fair Values of Company Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives assets, Carrying Amount	$ 0	$ 22
Derivatives liabilities, Carrying Amount	1,151	3,877
Derivatives assets, Fair Value	0	22
Derivatives liabilities, Fair Value	1,151	3,877
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Payable, Fair Value Disclosure	300,000	300,000
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Payable, Fair Value Disclosure	$ 297,000	$ 304,500

Derivative Financial Instruments - Additional Information (Detail) $ in Thousands, lb in Millions	12 Months Ended
	Mar. 31, 2019 USD ($) lb	Mar. 31, 2018 USD ($) lb
Derivatives, Fair Value [Line Items]
Foreign currency contract, maturity	1 year
Cost of Sales
Derivatives, Fair Value [Line Items]
Derivative gain (loss) to be recorded in income within 12 months, before tax	$ 46
Lead hedge forward contracts
Derivatives, Fair Value [Line Items]
Hedge forward contracts, maturity	1 year
Derivative, nonmonetary notional amount, mass \| lb	42.0	62.9
Total purchase price of derivative	$ 39,218	$ 72,207
Designated as Hedging Instrument \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Notional amount	42,318	54,164
Not Designated as Hedging Instrument \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Notional amount	$ 22,201	$ 28,486

Derivative Financial Instruments - Fair Value of Derivative Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	$ 0	$ 22
Derivatives liabilities, Fair Value	1,151	3,877
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	0	209
Derivatives liabilities, Fair Value	910	3,877
Designated as Hedging Instrument \| Prepaid and other current assets \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	0	209
Designated as Hedging Instrument \| Accrued expenses \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivatives liabilities, Fair Value	8	0
Designated as Hedging Instrument \| Accrued expenses \| Lead hedge forward contracts
Derivatives, Fair Value [Line Items]
Derivatives liabilities, Fair Value	902	3,877
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	0	0
Derivatives liabilities, Fair Value	241	187
Not Designated as Hedging Instrument \| Prepaid and other current assets \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	0	0
Not Designated as Hedging Instrument \| Accrued expenses \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivatives liabilities, Fair Value	241	187
Not Designated as Hedging Instrument \| Accrued expenses \| Lead hedge forward contracts
Derivatives, Fair Value [Line Items]
Derivatives liabilities, Fair Value	$ 0	$ 0

Derivative Financial Instruments - Effect of Derivative Instruments on Consolidated Condensed Statements of Income (Detail) - Designated as Hedging Instrument - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	$ (10,980)	$ (4,329)	$ 8,752
Gain (Loss) Reclassified from AOCI (Effective Portion)	(15,281)	3,142	6,236
Lead hedge forward contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	(12,531)	(805)	7,907
Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	1,551	(3,524)	845
Cost of Sales \| Lead hedge forward contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Reclassified from AOCI (Effective Portion)	(15,666)	5,860	5,803
Cost of Sales \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Reclassified from AOCI (Effective Portion)	$ 385	$ (2,718)	$ 433

Derivative Financial Instruments - Effect of Derivative Instruments (Detail) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ (1,856)	$ 180	$ (471)
Other (Income) Expense \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ (1,856)	$ 180	$ (471)

Income Taxes - Schedule of Income Tax Expense (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 30, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Current:
Federal		$ 6,377,000	$ 115,315,000	$ 30,362,000
State		5,027,000	3,461,000	4,855,000
Foreign		16,636,000	20,030,000	17,800,000
Total current income tax expense		28,040,000	138,806,000	53,017,000
Deferred income tax (benefit) expense
Federal		(5,031,000)	(9,551,000)	857,000
State		(669,000)	789,000	590,000
Foreign		(756,000)	(11,551,000)	8,000
Total deferred income tax (benefit) expense		(6,456,000)	(20,313,000)	1,455,000
Income tax expense	$ 13,483	$ 21,584,000	$ 118,493,000	$ 54,472,000

Income Taxes - Schedule of Earning Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
United States	$ 53,339	$ 74,440	$ 80,436
Foreign	128,872	163,886	132,259
Earnings before income taxes	$ 182,211	$ 238,326	$ 212,695

Income Taxes - Additional Information (Detail) - USD ($)		3 Months Ended			12 Months Ended
	Dec. 22, 2017	Dec. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Income Tax Contingency [Line Items]
Income taxes paid						$ 53,866,000	$ 28,044,000	$ 45,332,000
Blended rate					21.00%	31.55%	35.00%	35.00%
Impact of Tax Act			$ 4,106,000	$ 77,347,000	$ (13,483,000)	$ 83,400,000	$ 0
Provisional Transition Tax liability	$ 97,500,000
Tax Act - Transition Tax			7,800,000		5,290,000	7,800,000
Tax Act - Transition Tax			89,700,000		55,489,000	89,700,000
Net operating loss carryforwards carried forward indefinitely					102,792,000
Net operating loss carryforwards subject to expiration					(66,114,000)
Valuation allowance			15,255,000		17,519,000	15,255,000
Income Tax Expense (Benefit)		$ (13,483)			$ (21,584,000)	$ (118,493,000)	$ (54,472,000)
Effective income tax rates						11.90%	49.70%	25.60%
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent					12.30%	5.20%	13.50%
Income (Loss) from Continuing Operations before Income Taxes, Foreign					$ 128,872,000	$ 163,886,000	$ 132,259,000
Undistributed earnings of foreign subsidiaries			1,167,000,000			1,167,000,000	$ 1,260,000,000
Estimated change in unrecognized tax benefit in fiscal 2015					2,275,000
Tax related interest and penalties					$ 75,000	$ 116,000
Tax Rate of Swiss Subsidiary					4.00%	8.00%	5.00%
Income tax expense (benefit)					$ 13,483,000
Domestic Tax Authority
Income Tax Contingency [Line Items]
Increase (decrease) in tax rate					2.20%
Foreign
Income Tax Contingency [Line Items]
United States federal net operating loss carryforwards					$ 168,906,000
Valuation allowance			13,730,000		15,594,000	$ 13,730,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount					1,864,000
Income Tax Expense (Benefit)					$ 2,876,000
Increase (decrease) in tax rate					(0.90%)
Federal
Income Tax Contingency [Line Items]
United States federal net operating loss carryforwards					$ 1,438,000
Net operating loss carryforwards subject to expiration					630,000
Valuation allowance			630,000		1,027,000	630,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount					397,000
State
Income Tax Contingency [Line Items]
United States federal net operating loss carryforwards					33,900,000
Valuation allowance			$ 895,000		898,000	$ 895,000
Foreign Currency Translation Adjustment And Offset Adjustment To Net Operating Losses \| Foreign
Income Tax Contingency [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount					1,012,000
Alpha \| Federal
Income Tax Contingency [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount					$ 1,027,000

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Deferred tax assets:
Accounts receivable	$ 1,297	$ 1,790
Inventories	4,081	3,660
Net operating loss carryforwards	48,423	50,928
Accrued expenses	21,574	21,274
Deferred Tax Assets, Deferred Expense, Capitalized Research and Development Costs	7,061	0
Other assets	17,656	16,832
Gross deferred tax assets	100,092	94,484
Less valuation allowance	(17,519)	(15,255)
Total deferred tax assets	82,573	79,229
Deferred tax liabilities:
Property, plant and equipment	25,656	21,045
Intangible assets	96,826	46,058
Other liabilities	1,737	1,331
Total deferred tax liabilities	124,219	68,434
Deferred Tax Liabilities, Net	$ (41,646)
Net deferred tax assets		$ 10,795

Income Taxes - Reconciliation of Income Taxes at Statutory Rate (Detail) - USD ($)	3 Months Ended			12 Months Ended
	Dec. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
United States statutory income tax expense				$ 38,264,000	$ 75,196,000	$ 74,444,000
Impact of Tax Act		$ 4,106,000	$ 77,347,000	(13,483,000)	83,400,000	0
State income taxes, net of federal effect				3,285,000	3,146,000	3,677,000
Nondeductible expenses, domestic manufacturing deduction (fiscal 2018 and 2017) and other				2,677,000	1,078,000	1,993,000
Legal proceedings charge - European Competition Investigations - See Note 18				2,405,000	0	7,873,000
Net effect of GILTI, FDII, BEAT				2,320,000	0	0
Goodwill impairment - See Note 5				0	0	3,812,000
Effect of foreign operations				(16,763,000)	(35,048,000)	(39,377,000)
Valuation allowance				2,879,000	(9,279,000)	2,050,000
Income tax expense	$ 13,483			$ 21,584,000	$ 118,493,000	$ 54,472,000

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Reconciliation of Unrecognized Tax Benefits
Unrecognized tax benefits, beginning balance	$ 1,568	$ 1,450	$ 2,375
Increases related to current year tax positions	129	397	252
Increases related to the Alpha acquisition	7,840	0	0
Increases related to prior year tax positions	11,463	11	31
Decreases related to prior tax positions due to foreign currency translation	(544)	0	(352)
Decreases related to prior year tax positions	(93)	(1)	(678)
Lapse of statute of limitations	(198)	(289)	(178)
Unrecognized tax benefits, ending balance	$ 20,165	$ 1,568	$ 1,450

Retirement Plans - Net Periodic Pension Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment	$ (45)	$ (46)	$ (42)
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	371
Interest cost	631	658	664
Expected return on plan assets	(514)	(496)	(816)
Amortization and deferral	184	303	453
Net periodic benefit cost	301	465	672
International Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	997	1,025	871
Interest cost	1,831	1,795	1,848
Expected return on plan assets	(2,151)	(2,264)	(1,875)
Amortization and deferral	1,520	1,468	978
Net periodic benefit cost	$ 2,197	$ 2,024	$ 1,822

Retirement Plans - Change in Projected Benefit Obligations and Change in Plan Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
United States Plans
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at the beginning of the period	$ 16,713	$ 16,682
Service cost	0	0	$ 371
Interest cost	631	658	664
Benefits paid, inclusive of plan expenses	(1,061)	(1,037)
Plan curtailments and settlements	0	0
Experience loss	364	410
Foreign currency translation adjustment	0	0
Benefit obligation at the end of the period	16,647	16,713	16,682
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at the beginning of the period	13,928	12,731
Actual return on plan assets	758	1,731
Employer contributions	138	503
Benefits paid, inclusive of plan expenses	(1,061)	(1,037)
Defined Benefit Plan, Settlements and Curtailments, Plan Assets	0	0
Foreign currency translation adjustment	0	0
Fair value of plan assets at the end of the period	13,763	13,928	12,731
Funded status deficit	(2,884)		(2,785)
International Plans
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at the beginning of the period	82,033	74,478
Service cost	997	1,025	871
Interest cost	1,831	1,795	1,848
Benefits paid, inclusive of plan expenses	(1,758)	(2,153)
Plan curtailments and settlements	(1,130)	(52)
Experience loss	(261)	(2,705)
Foreign currency translation adjustment	(6,674)	9,645
Benefit obligation at the end of the period	75,038	82,033	74,478
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at the beginning of the period	38,757	34,323
Actual return on plan assets	2,109	688
Employer contributions	1,670	1,865
Benefits paid, inclusive of plan expenses	(1,758)	(2,153)
Defined Benefit Plan, Settlements and Curtailments, Plan Assets	(1,130)	(52)
Foreign currency translation adjustment	(2,857)	4,086
Fair value of plan assets at the end of the period	36,791	38,757	$ 34,323
Funded status deficit	$ (38,247)	$ (43,276)

Retirement Plans - Amounts Recognized in Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan amounts recognized in balance sheet	$ (41,131)	$ (46,061)
Accrued expenses
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan amounts recognized in balance sheet	(1,207)	(1,657)
Other liabilities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan amounts recognized in balance sheet	$ (39,924)	$ (44,404)

Retirement Plans - Pension Components Before Tax and Related Changes Net of Tax Recognized in AOCI (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Retirement Benefits [Abstract]
Prior service cost	$ 307	$ 385	$ 377
Net loss	(24,051)	(27,762)	(28,475)
Net amount recognized	$ 24,358	$ 28,147	$ 28,852

Retirement Plans - Summary Changes in Plan Assets and Benefit Obligations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Retirement Benefits [Abstract]
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	$ 0	$ 0	$ 0
Changes in plan assets and benefit obligations:
Net loss (gain) arising during the year	(99)	(1,953)	5,485
Effect of exchange rates on amounts included in AOCI	(1,984)	3,019	(2,275)
Amounts recognized as a component of net periodic benefit costs:
Amortization of prior service cost	(45)	(46)	(42)
Amortization or settlement recognition of net loss	(1,659)	(1,725)	(1,389)
Total recognized in other comprehensive income	$ (3,787)	$ (705)	$ 1,779

Retirement Plans - Summary of Recognized Components of Net Periodic Pension Cost Included in Accumulated Other Comprehensive Income (Detail) $ in Thousands	Mar. 31, 2019 USD ($)
Retirement Benefits [Abstract]
Prior service cost	$ (44)
Net loss	(1,185)
Net amount expected to be recognized	$ (1,229)

Retirement Plans - Summary of Accumulated Benefit Obligation Related to All Defined Pension Plans (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 16,647	$ 16,713
Accumulated benefit obligation	16,647	16,713
Fair value of plan assets	13,763	13,928
International Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	75,038	82,033
Accumulated benefit obligation	71,350	77,724
Fair value of plan assets	36,791	38,757
Unfunded Defined Benefit Plan \| United States Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	0	0
Accumulated benefit obligation	0	0
Unfunded Defined Benefit Plan \| International Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	32,320	33,124
Accumulated benefit obligation	30,328	31,270
Defined Benefit Plans With An Accumulated Benefit Obligation In Excess Of The Fair Value Of Plan Assets \| United States Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	16,647	16,713
Accumulated benefit obligation	16,647	16,713
Fair value of plan assets	13,763	13,928
Defined Benefit Plans With An Accumulated Benefit Obligation In Excess Of The Fair Value Of Plan Assets \| International Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	74,235	81,253
Accumulated benefit obligation	70,654	77,021
Fair value of plan assets	$ 36,077	$ 37,986

Retirement Plans - Significant Assumptions Used to Determine Net Periodic Benefit Cost (Detail)	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.90%	4.10%	3.90%
Expected return on plan assets	6.30%	6.80%	7.00%
International Plans \| Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate		1.40%	1.50%	1.80%
Expected return on plan assets		4.10%	3.60%	3.30%
Rate of compensation increase		1.80%	1.50%	1.50%
International Plans \| Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate		3.30%	3.50%	3.70%
Expected return on plan assets		6.00%	6.30%	6.50%
Rate of compensation increase		4.00%	4.00%	4.00%

Retirement Plans - Significant Assumptions Used to Determine Projected Benefit Obligations (Detail)	Mar. 31, 2019	Mar. 31, 2018
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.80%	3.90%
International Plans \| Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	1.00%	1.40%
Rate of compensation increase	2.00%	1.80%
International Plans \| Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.70%	3.30%
Rate of compensation increase	4.00%	4.00%

Retirement Plans - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Expected cash contributions to pension plans in 2014	$ 1,640
Defined Contribution Pension
Defined Benefit Plan Disclosure [Line Items]
Employer expenses	12,078	$ 8,931	$ 7,447
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Employer expenses	138	503
International Plans
Defined Benefit Plan Disclosure [Line Items]
Employer expenses	$ 1,670	$ 1,865
International Plans \| Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation percentage	65.00%
Minimum \| United States Plans \| Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Equity investments target range, minimum	40.00%
Maximum \| United States Plans \| Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Equity investments target range, minimum	75.00%

Retirement Plans - Summary of Pension Plan Investments Measured at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	$ 13,763	$ 13,928	$ 12,731
United States Plans \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	13,763	13,928
United States Plans \| Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	1,080	891
United States Plans \| Cash and Cash Equivalents \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	1,080	891
United States Plans \| US Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	8,275	9,864
United States Plans \| US Equity Securities \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	8,275	9,864
United States Plans \| International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
United States Plans \| International Equity Securities \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
United States Plans \| Fixed Income Funds
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	4,408	3,173
United States Plans \| Fixed Income Funds \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	4,408	3,173
International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	36,791	38,757	$ 34,323
International Plans \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	83	49
International Plans \| Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	36,708	38,708
International Plans \| Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	83	49
International Plans \| Cash and Cash Equivalents \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	83	49
International Plans \| International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	23,875	25,768
International Plans \| International Equity Securities \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0
International Plans \| International Equity Securities \| Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	23,875	25,768
International Plans \| Fixed Income Funds
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	12,833	12,940
International Plans \| Fixed Income Funds \| Quoted Price In Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0
International Plans \| Fixed Income Funds \| Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	$ 12,833	$ 12,940

Retirement Plans - Summary of Estimated Future Benefit Payments (Detail) $ in Thousands	Mar. 31, 2019 USD ($)
Defined Benefit Plan, Expected Future Benefit Payments, Rolling Maturity [Abstract] (Deprecated 2017-01-31)
2020	$ 2,713
2021	2,783
2022	3,072
2023	3,392
2024	3,536
Years 2025-2029	$ 21,106

Stockholders' Equity and Noncontrolling Interests - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Dec. 07, 2018	Mar. 31, 2019	Mar. 31, 2018
Class of Stock [Line Items]
Nonvested stock, weighted average remaining contractual term		20 months
Preferred stock, shares issued (in shares)		0	0
Preferred stock, shares outstanding (in shares)		0	0
Preferred stock, shares authorized (in shares)		1,000,000	1,000,000
Preferred stock, par value (usd per share)		$ 0.01	$ 0.01
Number of shares of common stock purchased		726,347	1,756,831
Repurchased common stock value		$ 56,436	$ 121,191
Treasury stock, shares (in shares)		12,227,773	12,680,105
Shares issued in ESPP (USD per share)		$ 62.55
Shares issued in acquisition (in shares)		1,177,630
Accelerated Share Repurchase Agreement [Member]
Class of Stock [Line Items]
Stock Repurchased and Retired During Period, Shares			1,495,714
Accelerated Share Repurchases, Settlement (Payment) or Receipt			$ 100,000
Accelerated Share Repurchases, Final Price Paid Per Share			$ 66.86
Alpha
Class of Stock [Line Items]
Initial purchase consideration	$ 750,000
Payments to acquire businesses	650,000
Shares issued in acquisition, value	$ 93,268
Shares issued in acquisition (USD per share)	$ 84.92
Common Stock \| Alpha
Class of Stock [Line Items]
Shares issued in employee stock purchase plan (in shares)		3,256
Shares issued in acquisition (in shares)	1,177,630

Change in Number of Shares of Common Stock Outstanding (Detail) - shares	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares outstanding, beginning balance	41,915,000	43,447,536	43,189,502
Purchase of treasury stock	(726,347)	(1,756,831)
Shares issued in acquisition (in shares)	1,177,630
Shares issued as part of equity-based compensation plans, net of equity awards surrendered for option price and taxes	254,467	224,295	258,034
Shares outstanding, ending balance	42,620,750	41,915,000	43,447,536

Components of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ (41,717)	$ (152,824)	$ (97,349)
Before Reclassifications	(114,029)	112,279	(52,504)
Amount Reclassified from AOCI	13,064	(1,172)	(2,971)
Ending Balance	(142,682)	(41,717)	(152,824)
Pension funded status adjustment
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(22,503)	(25,555)	(21,861)
Before Reclassifications	339	1,692	(4,659)
Amount Reclassified from AOCI	1,373	1,360	965
Ending Balance	(20,791)	(22,503)	(25,555)
Net unrealized gain (loss) on derivative instruments
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(3,425)	1,975	388
Before Reclassifications	(8,396)	(2,868)	5,523
Amount Reclassified from AOCI	11,691	(2,532)	(3,936)
Ending Balance	(130)	(3,425)	1,975
Foreign currency translation adjustment
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(15,789)	(129,244)	(75,876)
Before Reclassifications	(105,972)	113,455	(53,368)
Amount Reclassified from AOCI	0	0	0
Ending Balance	$ (121,761)	$ (15,789)	$ (129,244)

Stockholders Equity and Noncontrolling Interests Reclassification from Accumulated Other Comprehensive Income (Details) - USD ($)	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Mar. 31, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Cost of goods sold									$ 2,104,612,000	$ 1,920,030,000	$ 1,713,115,000
Income tax expense		$ 13,483							21,584,000	118,493,000	54,472,000
Net earnings attributable to EnerSys stockholders	$ (18,538,000)	$ (48,417,000)	$ (47,424,000)	$ (45,860,000)	$ (54,018,000)	$ 25,847,000	$ (43,222,000)	$ (48,201,000)	(160,239,000)	(119,594,000)	(160,214,000)
Net unrealized gain (loss) on derivative instruments \| Reclassification out of Accumulated Other Comprehensive Income
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Cost of goods sold									15,281,000	(3,142,000)	(6,236,000)
Income tax expense									(3,590,000)	610,000	2,300,000
Net earnings attributable to EnerSys stockholders									11,691,000	(2,532,000)	(3,936,000)
Pension funded status adjustment \| Reclassification out of Accumulated Other Comprehensive Income
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Prior service costs and deferrals									1,704,000	1,771,000	1,431,000
Income tax expense									(331,000)	(411,000)	(466,000)
Net earnings attributable to EnerSys stockholders									$ 1,373,000	$ 1,360,000	$ 965,000

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Redeemable Noncontrolling Interests (Detail) $ in Thousands	12 Months Ended
Redeemable Noncontrolling Interests (Detail) $ in Thousands	Mar. 31, 2017 USD ($)
Temporary Equity, Number of Shares, Redemption Value and Other Disclosures [Abstract]
Redeemable noncontrolling interest, beginning balance	$ 5,997
Redeemable noncontrolling interests recognized in acquisitions of Powertech Batteries and Energy Leader Batteries India Limited	(2,021)
Deconsolidation of joint venture	(4,035)
Foreign currency translation adjustment	59
Redeemable noncontrolling interest, ending balance	$ 0

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants	3,750,392
Stock options granted	192,700	169,703	242,068
Stock-based compensation expense	$ 3,251	$ 700	$ 1,705
Stock-based compensation expense, net of tax	$ 634	$ 2,741	$ 457
Market price per unit of stock award	$ 75.32	$ 73.39	$ 65.88
Unrecognized compensation expense associated with non-vested incentive awards outstanding	$ 37,187
Nonvested stock, weighted average remaining contractual term	20 months
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market price per unit of stock award	$ 69.43
Stock unit grant during period	241,105
Restricted Shares Restricted Stock Units and Market Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 19,357	$ 16,712	$ 17,480
Stock unit grant during period	1,441	1,345	1,239
Equity-based compensation expense, tax benefit	$ 3,085	$ 3,325	$ 4,210
Non Employee Directors \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted	35,065	33,408	25,708
Market price per unit of stock award	$ 46.30	$ 46.24	$ 69.97
Management \| Nonqualified Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted	192,700
Vesting period, in years	3 years
Management \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market price per unit of stock award	$ 75.17	$ 83.14	$ 57.60
Stock unit grant during period	204,599	161,229	237,358
Management \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market price per unit of stock award	$ 68.48
Stock unit grant during period	45,883
Management \| Market Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market price per unit of stock award	$ 86.23	$ 105.74	$ 70.79
Stock unit grant during period	36,646	60,187	83,720
Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants	4,173,554
Stock Options Issued In Fiscal 2010 \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options expiration period (in years)	10 years

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Number of options
Number of Options outstanding, Beginning Balance	545,590	451,668	210,297
Number of Options, Granted	192,700	169,703	242,068
Number of Options, Exercised	(171,630)	(62,197)	(263)
Number of Options, Forfeited	(11,754)	(11,495)
Number of Options, Expired		2,089	434
Number of Options outstanding, Ending Balance	554,906	545,590	451,668	210,297
Number of Options, Exerciseable	186,823
Number of Options, Vested and Expected to Vest	545,299
Options outstanding, Weighted Average Remaining Contract Term
Options outstanding, Weighted Average Remaining Contract Term (Years)	8 years	8 years 4 months 24 days	8 years 4 months 24 days	8 years 6 months
Options exercisable, Weighted Average Remaining Contract Term (Years)	6 years 10 months 24 days
Options vested and expected to vest, Weighted Average Remaining Contract Term (Years)	8 years
Weighted average exercise price
Options outstanding, Weighted Average Exercise Price, Beginning Balance	$ 68.65	$ 62.29	$ 67.54
Weighted Average Exercise Price, Granted	75.17	83.14	57.60
Weighted Average Exercise Price, Exercised	63.66	63.44	18.25
Weighted Average Exercise Price, Expired	75.17	70.22
Weighted Average Exercise Price, Forfeited		18.25	18.25
Options outstanding, Weighted Average Exercise Price, Ending Balance	72.31	$ 68.65	$ 62.29	$ 67.54
Options exercisable, Weighted Average Exercise Price	69.34
Weighted Average Exercise Price, Vested and Expected to Vest	$ 72.24
Aggregate intrinsic value
Options outstanding, Aggregate Intrinsic Value, Beginning Balance	$ 2,679	$ 7,520	$ 218
Options exercised, aggregate intrinsic value	2,707	1,132	12
Options forfeited, aggregate intrinsic value	0	75
Options expired, aggregate intrinsic value		137	15
Options outstanding, Aggregate Intrinsic Value, Ending Balance	1,040	$ 2,679	$ 7,520	$ 218
Options exercisable, Aggregate Intrinsic Value	452
Options vested and expected to vest, aggregate intrinsic value	$ 1,038

Stock-Based Compensation - Summary of Information Regarding Stock Options Outstanding and Exercisable (Detail)	12 Months Ended
	Mar. 31, 2019 $ / shares shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Options \| shares	554,906
Weighted Average Remaining Contractual Life	8 years
Weighted Average Exercise Price \| $ / shares	$ 72.31

Stock Based Compensation Stock-Based Compensation - Summary of Assumptions Used for Market Share Units (Details) - $ / shares	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options	554,906
Weighted Average Remaining Contractual Life	8 years
Weighted Average Exercise Price	$ 72.31
Performance Market Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	2.66%	1.57%	0.94%
Dividend yield	0.00%	0.00%	0.00%
Time of maturity, in years	3 years	3 years	3 years
Expected volatility	26.41%	27.49%	31.74%
Market Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	2.77%	2.08%	1.41%
Dividend yield	0.93%	0.84%	1.22%
Time of maturity, in years	6 years	6 years	6 years
Expected volatility	26.80%	29.20%	30.40%
$55.00-$60.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options	137,599
Weighted Average Remaining Contractual Life	7 years 1 month 6 days
Weighted Average Exercise Price	$ 57.60
$65.01-$70.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options	73,368
Weighted Average Remaining Contractual Life	5 years 9 months 18 days
Weighted Average Exercise Price	$ 68.82
$75.01-$83.14
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options	343,939
Weighted Average Remaining Contractual Life	8 years 9 months 18 days
Weighted Average Exercise Price	$ 78.95

Stock-Based Compensation - Summary of Changes in Restricted Stock Units and Market Share Units (Detail) - $ / shares	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Granted	$ 75.32	$ 73.39	$ 65.88
Restricted Stock Units (RSUs)
Number of RSU and MSU
Number of RSU and MSU, Non-vested awards, Beginning Balance	633,751
Number of RSU and MSU, Granted	241,105
Number of RSU and MSU, Stock dividend	6,087
Number of RSU and MSU, Vested	(148,487)
Number of RSU and MSU, cancelled	(10,809)
Number of RSU and MSU, Non-vested awards, Ending Balance	721,647	633,751
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance	$ 56.60
Weighted Average Grant Date Fair Value, Granted	69.43
Weighted Average Grant Date Fair Value, Stock dividend	56.81
Weighted Average Grant Date Fair Value, Vested	68.55
Weighted Average Grant Date Fair Value, Canceled	72.56
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance	$ 57.72	$ 56.60
Market Share Unit Number (MSU)
Number of RSU and MSU
Number of RSU and MSU, Non-vested awards, Beginning Balance	349,941
Number of RSU and MSU, Granted	36,646
Number of RSU and MSU, Stock dividend	3,131
Number of RSU and MSU, Performance factor	143
Number of RSU and MSU, Vested	(3,482)
Number of RSU and MSU, cancelled	(33,795)
Number of RSU and MSU, Non-vested awards, Ending Balance	352,584	349,941
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance	$ 70.22
Weighted Average Grant Date Fair Value, Granted	85.84
Weighted Average Grant Date Fair Value, Stock dividend	72.60
Weighted Average Grant Date Fair Value, Performance factor	75.48
Weighted Average Grant Date Fair Value, Vested	59.94
Weighted Average Grant Date Fair Value, Canceled	62.21
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance	$ 72.83	$ 70.22
Performance condition-based Share Units (PSU)
Number of RSU and MSU
Number of RSU and MSU, Non-vested awards, Beginning Balance	0
Number of RSU and MSU, Granted	45,883
Number of RSU and MSU, Stock dividend	320
Number of RSU and MSU, Performance factor	0
Number of RSU and MSU, Vested	0
Number of RSU and MSU, cancelled	(3,677)
Number of RSU and MSU, Non-vested awards, Ending Balance	42,526	0
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance	$ 0
Weighted Average Grant Date Fair Value, Granted	68.48
Weighted Average Grant Date Fair Value, Stock dividend	68.48
Weighted Average Grant Date Fair Value, Performance factor	0
Weighted Average Grant Date Fair Value, Vested	0
Weighted Average Grant Date Fair Value, Canceled	68.48
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance	$ 68.48	$ 0

Earnings Per Share - Weighted Average Common Shares Basic and Common Shares Diluted (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Mar. 31, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net earnings attributable to EnerSys stockholders	$ 18,538	$ 48,417	$ 47,424	$ 45,860	$ 54,018	$ (25,847)	$ 43,222	$ 48,201	$ 160,239	$ 119,594	$ 160,214
Basic (in shares)									42,335,023	42,612,036	43,389,333
Dilutive effect of:
Common shares from exercise and lapse of equity awards, net of shares assumed reacquired (in shares)									673,929	507,820	623,210
Diluted weighted-average number of common shares outstanding (in shares)									43,008,952	43,119,856	44,012,543
Basic earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.43	$ 1.14	$ 1.13	$ 1.09	$ 1.29	$ (0.61)	$ 1.01	$ 1.11	$ 3.79	$ 2.81	$ 3.69
Diluted earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.42	$ 1.12	$ 1.11	$ 1.08	$ 1.27	$ (0.61)	$ 1.00	$ 1.09	$ 3.73	$ 2.77	$ 3.64
Anti-dilutive equity awards not included in diluted weighted-average common shares (in shares)									355,728,000	59,482,000	1,295,000

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Earnings Per Share - Additional Information (Detail) - Accelerated Share Repurchase Agreement [Member]	12 Months Ended
	Mar. 31, 2018 $ / shares shares
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Stock Repurchased and Retired During Period, Shares \| shares	1,495,714
Accelerated Share Repurchases, Final Price Paid Per Share \| $ / shares	$ 66.86

Commitments, Contingencies and Litigation - Additional Information (Detail) € in Thousands			1 Months Ended			3 Months Ended			12 Months Ended
	Jun. 11, 2013 USD ($)	Jun. 11, 2013 EUR (€)	Jul. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2018 EUR (€)	Mar. 31, 2019 USD ($) Employee	Mar. 31, 2018 USD ($)
Commitments, Contingencies And Litigation [Line Items]
Reserves for anti-competition investigations							$ 2,326,000		$ 7,258,000	$ 2,326,000
Reserves of environmental liabilities									$ 1,081,000	1,109,000
Company number of employees \| Employee									11,000
Percentage of employees covered by collective bargaining agreements									27.00%
Percentage of collective bargaining agreements that expire in next twelve months									10.00%
Average term of collective bargaining agreements									2 years
Longest term of collective bargaining agreements									3 years
Litigation Settlement, Amount Awarded from Other Party	$ 2,756,000	€ 2,000				$ 2,843
Belgium Anti-Competition Proceeding
Commitments, Contingencies And Litigation [Line Items]
Penalties paid relating to anti-competition investigations					$ 1,962,000
Legal proceedings charge									$ 2,402
Reserves for anti-competition investigations							2,326,000		0	2,326,000
Germany Anti-competition Proceedings
Commitments, Contingencies And Litigation [Line Items]
Penalties paid relating to anti-competition investigations				$ 14,811,000
Legal proceedings charge									7,258,000
Reserves for anti-competition investigations							0		$ 7,258,000	$ 0
Dutch Anti-Competition Proceedings [Member]
Commitments, Contingencies And Litigation [Line Items]
Penalties paid relating to anti-competition investigations			$ 11,229,000
Settled Litigation [Member]
Commitments, Contingencies And Litigation [Line Items]
Litigation Settlement, Amount Awarded from Other Party							$ 2,843,000	€ 2,500

Restructuring Plans and Other Exit Charges - Additional Information (Detail)	3 Months Ended									12 Months Ended				15 Months Ended	33 Months Ended
	Mar. 31, 2019 USD ($)	Dec. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jul. 01, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Oct. 01, 2017 USD ($)	Jul. 02, 2017 USD ($)	Jul. 03, 2016 USD ($)	Mar. 31, 2019 USD ($) Employee	Mar. 31, 2018 USD ($) Employee	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Jun. 30, 2016 USD ($) Employee	Dec. 31, 2017 USD ($) Employee
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges	$ 26,457,000	$ 5,392,000	$ 1,121,000	$ 1,739,000	$ 1,064,000	$ 1,808,000	$ 1,776,000	$ 833,000		$ 34,709,000	$ 5,481,000	$ 7,160,000
Write-off of assets relating to restructuring and other exit charges										26,308,000	3,736,000	1,435,000
Restructuring Related To Sale Of Geräte- und Akkumulatorenwerk Zwickau GmbH
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										4,930,000
Restructuring Charges Relating To Dissolving Joint Venture In Tunisia
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										$ 957,000
EMEA \| Restructurings Related to Improving Efficiency of Manufacturing, Sales, and Engineering Operations In EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											85,000	1,251,000	$ 5,232,000		$ 6,568,000
Expected reduction in number of employees \| Employee															130
Restructuring charges, cash charges related to employee severance and other charges											499,000	3,037,000	2,993,000
EMEA \| Restructurings Related to Improving Efficiency Related to Motive Power Production in EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											1,610,000	3,104,000
Expected reduction in number of employees \| Employee										45
Write-off of assets relating to restructuring and other exit charges										$ 4,714,000
Restructuring charges, cash charges related to employee severance and other charges										1,682,000	2,403,000	749,000
EMEA \| Restructurings Related to Improving Efficiency Related to Supply Chain and General Operations
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										3,104,000	$ 2,260,000
Expected reduction in number of employees \| Employee											85
Restructuring reserve	1,061,000									1,061,000
Write-off of assets relating to restructuring and other exit charges											$ 7,700,000
Restructuring charges, cash charges related to employee severance and other charges										2,844,000	1,350,000
Expected remaining restructuring charges	2,200,000									2,200,000
EMEA \| Restructurings Related To Improving Efficiencies Of Reserve Power Operations In EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										$ 347,000
Expected reduction in number of employees \| Employee										35
Restructuring reserve	262,000									$ 262,000
Write-off of assets relating to restructuring and other exit charges										2,500,000
Restructuring charges, cash charges related to employee severance and other charges										83,000
EMEA \| Employee Severance \| Restructurings Related to Improving Efficiency of Manufacturing, Sales, and Engineering Operations In EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges															$ 6,161,000
EMEA \| Other Charges \| Restructurings Related to Improving Efficiency of Manufacturing, Sales, and Engineering Operations In EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges															$ 407,000
EMEA \| Non Cash Charges \| Restructurings Related to Improving Efficiency Related to Supply Chain and General Operations
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											69,000
Asia \| Restructurings Related To Completing Transfer of Equipment and Clean-Up of Manufacturing Facility in Jiangdu
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											212,000	779,000
Write-off of assets relating to restructuring and other exit charges											991,000
Restructuring charges, cash charges related to employee severance and other charges											341,000	$ 648,000
Asia \| Restructuring Program To Improve Efficiencies Of Operations In Asia And Conversion Of India Operations
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										$ 2,772,000
Expected reduction in number of employees \| Employee										150
Restructuring reserve	1,139,000									$ 1,139,000
Write-off of assets relating to restructuring and other exit charges										4,500,000
Restructuring charges, cash charges related to employee severance and other charges										1,683,000
Asia \| Restructuring Related To Improving Profitability In India
Restructuring Cost and Reserve [Line Items]
Write-off of assets relating to restructuring and other exit charges										660,000
Asia \| Non Cash Charges \| Restructuring Program To Improve Efficiencies Of Operations In Asia And Conversion Of India Operations
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										771,000
Americas \| Restructuring Related to Improving the Efficiency of Manufacturing Operations in the Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges									$ 174,000				1,488,000	$ 2,379,000
Expected reduction in number of employees \| Employee														100
Restructuring charges, cash charges related to employee severance and other charges									924,000				119,000
Americas \| Restructurings Related to Improving Efficiencies of General Operations in the Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											$ 960,000
Expected reduction in number of employees \| Employee											60
Write-off of assets relating to restructuring and other exit charges											$ 960,000
Restructuring charges, cash charges related to employee severance and other charges										207,000	755,000
Americas \| Restructurings Related To Improving Efficiencies Of Operations In The Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										$ 1,970,000
Expected reduction in number of employees \| Employee										100
Restructuring reserve	490,000									$ 490,000
Write-off of assets relating to restructuring and other exit charges										4,600,000
Restructuring charges, cash charges related to employee severance and other charges										1,480,000
Americas \| Employee Severance \| Restructuring Related to Improving the Efficiency of Manufacturing Operations in the Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges														$ 1,043,000
Americas \| Pension Curtailment \| Restructuring Related to Improving the Efficiency of Manufacturing Operations in the Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges													313,000	313,000
Americas \| Non Cash Charges \| Restructuring Related to Improving the Efficiency of Manufacturing Operations in the Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges									$ 718,000				$ 305,000	$ 1,023,000
Americas \| Non Cash Charges \| Restructurings Related To Improving Efficiencies Of Operations In The Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										2,095,000
Americas \| Facility Closing
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges							75,000
Gain (Loss) on Sale of Properties							$ (210,000)
Americas \| Inventory Write-Off \| Restructurings Related to Improving Efficiencies of General Operations in the Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											3,457,000
Closure Of Facility In Targovishte, Bulgaria
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										17,652,000
Expected cost remaining	$ 30,000,000									30,000,000
Closure Of Facility In Targovishte, Bulgaria \| Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										2,694,000
Closure Of Facility In Targovishte, Bulgaria \| Inventory Write-Off
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										2,590,000
Closure Of Facility In Targovishte, Bulgaria \| Fixed Asset Write Offs
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										14,958,000
South Africa Joint Venture Business Exit
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											3,292,000
South Africa Joint Venture Business Exit \| Employee Severance
Restructuring Cost and Reserve [Line Items]
Write-off of assets relating to restructuring and other exit charges											717,000
Restructuring charges, cash charges related to employee severance and other charges											2,575,000
South Africa Joint Venture Business Exit \| Inventory Write-Off
Restructuring Cost and Reserve [Line Items]
Write-off of assets relating to restructuring and other exit charges											2,157,000
South Africa Joint Venture Business Exit \| Change in Estimate of Contract losses
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											1,099,000
South Africa Joint Venture Business Exit \| Deconsolidation of Joint Venture
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											$ (341,000)
Cost of Sales \| Asia \| Non Cash Charges \| Restructuring Related To Improving Profitability In India
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										$ 526,000

Restructuring Plans and Other Exit Charges - Acquisition and Non-Acquisition Related Restructuring Reserve (Details) - Non-Acquisition Related Restructuring Plans - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Restructuring Reserve [Roll Forward]
Beginning balance	$ 2,909	$ 2,812	$ 2,989
Accrued	8,193	5,202	5,308
Costs incurred	(7,979)	(5,423)	(5,358)
Foreign currency impact and other	(171)	318	(127)
Ending balance	2,952	2,909	2,812
Employee Severance
Restructuring Reserve [Roll Forward]
Beginning balance	2,893	2,668	2,964
Accrued	6,554	4,757	4,566
Costs incurred	(6,893)	(4,849)	(4,754)
Foreign currency impact and other	(198)	317	(108)
Ending balance	2,356	2,893	2,668
Other
Restructuring Reserve [Roll Forward]
Beginning balance	16	144	25
Accrued	1,639	445	742
Costs incurred	(1,086)	(574)	(604)
Foreign currency impact and other	27	1	(19)
Ending balance	$ 596	$ 16	$ 144

Warranty (Detail) - USD ($) $ in Thousands	12 Months Ended
Warranty (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Product Warranty Accrual [Roll Forward]
Balance at beginning of year	$ 50,602	$ 46,116	$ 48,422
Current year provisions	23,679	21,706	17,852
Costs incurred	(25,053)	(18,820)	(15,945)
Warranty reserves of acquired business - Alpha	7,535	0	0
Foreign currency translation adjustment	(2,195)	1,600	(4,213)
Balance at end of year	$ 54,568	$ 50,602	$ 46,116

Other (Income) Expense, Net (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Other Income and Expenses [Abstract]
Foreign exchange transaction (gains) losses	$ (3,044)	$ 5,499	$ (662)
Non-service components of pension expense	1,502	1,464	1,252
Other	928	556	1,631
Total	$ (614)	$ 7,519	$ 2,221

Business Segments - Schedule of Summarized Financial Information by Reportable Segments Segments (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Mar. 31, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Net sales	$ 796,603	$ 680,022	$ 660,462	$ 670,930	$ 683,042	$ 658,935	$ 617,289	$ 622,625	$ 2,808,017	$ 2,581,891	$ 2,367,149
Intersegment sales									186,558	186,052	141,773
Total operating earnings	34,978	49,951	63,357	64,179	67,725	68,785	64,364	69,972	212,465	270,846	237,113
Inventory adjustment relating to exit activities - EMEA	(3,516)	(3,747)			(3,457)				(10,379)	(3,457)	(2,157)
Restructuring charges	(26,457)	$ (5,392)	$ (1,121)	$ (1,739)	(1,064)	$ (1,808)	$ (1,776)	$ (833)	(34,709)	(5,481)	(7,160)
Impairment of goodwill, indefinite-lived intangibles and fixed assets - See Note 5									0	0	(12,216)
Gain on sale of facility - Asia									258	(116)	7
Property, plant, and equipment, net	409,439				390,260				409,439	390,260	348,549
Capital Expenditures									70,372	69,832	50,072
Depreciation and amortization									63,348	54,317	53,945
Reserve Power
Segment Reporting Information [Line Items]
Net sales									1,416,173	1,247,900	1,142,327
Motive Power
Segment Reporting Information [Line Items]
Net sales									1,391,844	1,333,991	1,224,822
Americas
Segment Reporting Information [Line Items]
Net sales									1,690,912	1,429,888	1,332,353
Intersegment sales									28,753	29,513	26,039
Total operating earnings									186,814	189,466	191,801
Inventory step up to fair value relating to acquisition - Americas									(7,263)	0	0
Inventory adjustment relating to exit activities - EMEA									0	(3,457)	0
Restructuring charges									(4,066)	(1,246)	(892)
Impairment of goodwill, indefinite-lived intangibles and fixed assets - See Note 5									0	0	(9,346)
Property, plant, and equipment, net	257,559				210,998				257,559	210,998	190,169
Capital Expenditures									45,029	46,905	34,809
Depreciation and amortization									40,675	30,421	30,204
Europe
Segment Reporting Information [Line Items]
Inventory adjustment relating to exit activities - EMEA									(2,590)	0	(2,157)
Legal proceedings charge									(4,437)	0	(23,725)
EMEA
Segment Reporting Information [Line Items]
Net sales									860,563	849,420	763,013
Intersegment sales									123,274	133,164	93,150
Total operating earnings									71,963	77,671	77,376
Restructuring charges									(26,989)	(4,023)	(5,487)
Impairment of goodwill, indefinite-lived intangibles and fixed assets - See Note 5									0	0	(4,670)
Property, plant, and equipment, net	94,932				118,263				94,932	118,263	100,042
Capital Expenditures									18,972	18,392	13,733
Depreciation and amortization									15,128	16,198	15,693
Asia
Segment Reporting Information [Line Items]
Net sales									256,542	302,583	271,783
Intersegment sales									34,531	23,375	22,584
Total operating earnings									3,213	12,647	14,994
Inventory adjustment relating to exit activities - EMEA									(526)	0	0
Restructuring charges									(3,654)	(212)	(781)
Property, plant, and equipment, net	$ 56,948				$ 60,999				56,948	60,999	58,338
Capital Expenditures									6,371	4,535	1,530
Depreciation and amortization									$ 7,545	$ 7,698	$ 8,048

Business Segments - Additional Information (Detail) $ in Thousands	12 Months Ended
	Mar. 31, 2019 USD ($) Country	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Operations in number of countries \| Country	100
Property, plant, and equipment, net	$ 409,439	$ 390,260	$ 348,549
United States
Segment Reporting Information [Line Items]
Percentage of sales to customers	48.50%	49.20%	50.00%
Property, plant, and equipment, net	$ 202,985	$ 176,144

Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Mar. 31, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 796,603	$ 680,022	$ 660,462	$ 670,930	$ 683,042	$ 658,935	$ 617,289	$ 622,625	$ 2,808,017	$ 2,581,891	$ 2,367,149
Gross profit	202,266	164,546	160,880	165,334	167,388	167,310	160,248	163,458	693,026	658,404	651,877
Operating earnings	34,978	49,951	63,357	64,179	67,725	68,785	64,364	69,972	212,465	270,846	237,113
Net earnings	18,546	48,614	47,447	46,020	54,139	(25,779)	43,151	48,322	160,627	119,833	158,223
Net earnings attributable to EnerSys stockholders	$ 18,538	$ 48,417	$ 47,424	$ 45,860	$ 54,018	$ (25,847)	$ 43,222	$ 48,201	$ 160,239	$ 119,594	$ 160,214
Basic earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.43	$ 1.14	$ 1.13	$ 1.09	$ 1.29	$ (0.61)	$ 1.01	$ 1.11	$ 3.79	$ 2.81	$ 3.69
Diluted earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.42	$ 1.12	$ 1.11	$ 1.08	$ 1.27	$ (0.61)	$ 1.00	$ 1.09	$ 3.73	$ 2.77	$ 3.64

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.