EnerSys (ENS) 10-K 26 May 21 2021 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Mar. 31, 2021	May 21, 2021	Oct. 04, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Mar. 31, 2021
Current Fiscal Year End Date	--03-31
Document Transition Report	false
Entity File Number	001-32253
Entity Registrant Name	ENERSYS
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	23-3058564
Entity Address, Address Line One	2366 Bernville Road
Entity Address, City or Town	Reading
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19605
City Area Code	610
Local Phone Number	208-1991
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	ENS
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Entity Public Float			$ 2,908,005,701
Entity Common Stock, Shares Outstanding (in shares)		42,831,879
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement for its Annual Meeting of Stockholders to be held on or about August 5, 2021 are incorporated by reference in Part III of this Annual Report.
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Central Index Key	0001289308

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Current assets:
Cash and cash equivalents	$ 451,808	$ 326,979
Accounts receivable, net of allowance for doubtful accounts (2021–$12,992; 2020–$15,246)	603,581	595,873
Inventories	518,247	519,460
Prepaid and other current assets	117,681	120,593
Total current assets	1,691,317	1,562,905
Property, plant, and equipment, net	497,056	480,014
Goodwill	705,593	663,936
Other intangible assets, net	430,898	455,685
Deferred taxes	65,212	55,803
Other assets	72,721	83,355
Total assets	3,462,797	3,301,698
Current liabilities:
Short-term debt	34,153	46,544
Current portion of finance leases	236	162
Accounts payable	323,876	281,873
Accrued expenses	318,723	271,740
Total current liabilities	676,988	600,319
Long-term debt, net of unamortized debt issuance costs	969,618	1,104,731
Finance leases	435	407
Deferred taxes	76,412	78,363
Other liabilities	195,768	213,816
Total liabilities	1,919,221	1,997,636
Commitments and contingencies
Equity:
Preferred Stock, $0.01 par value, 1,000,000 shares authorized, no shares issued or outstanding at March 31, 2021 and at March 31, 2020	0	0
Common Stock, $0.01 par value per share, 135,000,000 shares authorized, 55,552,810 shares issued and 42,753,020 shares outstanding at March 31, 2021; 55,114,808 shares issued and 42,323,305 shares outstanding at March 31, 2020	555	551
Additional paid-in capital	554,168	529,100
Treasury stock at cost, 12,799,790 shares held as of March 31, 2021 and 12,791,503 shares held as of March 31, 2020	(563,481)	(564,376)
Retained earnings	1,669,751	1,556,980
Accumulated other comprehensive loss	(115,883)	(215,006)
Contra equity - indemnification receivable	(5,355)	(6,724)
Total EnerSys stockholders’ equity	1,539,755	1,300,525
Nonredeemable noncontrolling interests	3,821	3,537
Total equity	1,543,576	1,304,062
Total liabilities and equity	$ 3,462,797	$ 3,301,698

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Statement of Financial Position [Abstract]
Allowance for credit loss	$ 12,992	$ 15,246
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)	55,552,810	55,114,808
Common stock, shares outstanding (in shares)	42,753,020	42,323,305
Treasury stock, shares (in shares)	12,799,790	12,791,503

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Net sales	$ 2,977,932	$ 3,087,868	$ 2,808,017
Cost of goods sold	2,238,782	2,301,148	2,104,612
Inventory step up to fair value relating to acquisitions and exit activities	0	1,854	10,379
Gross profit	739,150	784,866	693,026
Operating expenses	482,401	529,643	441,415
Restructuring and other exit charges	40,374	20,766	34,709
Impairment of goodwill	0	39,713	0
Impairment of indefinite-lived intangibles	0	4,549	0
Legal proceedings charge, net	0	0	4,437
Operating earnings	216,375	190,195	212,465
Interest expense	38,436	43,673	30,868
Other (income) expense, net	7,804	(415)	(614)
Earnings before income taxes	170,135	146,937	182,211
Income tax expense	26,761	9,821	21,584
Net earnings	143,374	137,116	160,627
Net earnings attributable to noncontrolling interests	0	0	388
Net earnings attributable to EnerSys stockholders	$ 143,374	$ 137,116	$ 160,239
Net earnings per common share attributable to EnerSys stockholders:
Basic (usd per share)	$ 3.37	$ 3.23	$ 3.79
Diluted (usd per share)	3.32	3.20	3.73
Dividends per common share (usd per share)	$ 0.70	$ 0.70	$ 0.70
Weighted-average number of common shares outstanding:
Basic (in shares)	42,548,449	42,411,834	42,335,023
Diluted (in shares)	43,224,403	42,896,775	43,008,952

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net earnings	$ 143,374	$ 137,116	$ 160,627
Other comprehensive (loss) income:
Net unrealized gain (loss) on derivative instruments, net of tax	6,283	(5,793)	3,295
Pension funded status adjustment, net of tax	1,847	(2,003)	1,712
Foreign currency translation adjustment	91,277	(64,721)	(106,555)
Total other comprehensive gain (loss), net of tax	99,407	(72,517)	(101,548)
Total comprehensive income	242,781	64,599	59,079
Comprehensive gain (loss) attributable to noncontrolling interests	284	(193)	(195)
Comprehensive income attributable to EnerSys stockholders	$ 242,497	$ 64,792	$ 59,274

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Total EnerSys Stockholders’ Equity	Preferred Stock	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Contra-Equity	Non- redeemable Non- Controlling Interests
Beginning Balance at Mar. 31, 2018	$ 1,201,111	$ 1,195,675	$ 0	$ 546	$ 477,288	$ (560,991)	$ 1,320,549	$ (41,717)	$ 0	$ 5,436
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	22,608	22,608			22,608					0
Exercise of stock options	9,048	9,048		2	9,046
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)		0
Purchase of common stock	(56,436)	(56,436)				(56,436)
Reissuance of treasury stock, on LIFO basis, towards Alpha purchase consideration	93,268	93,268			6,805	86,463
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)
Net earnings	160,627	160,239					160,239			388
Dividends	(29,743)	(29,743)			720		(30,463)
Dissolution of joint venture	(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	(106,555)	(105,972)						(105,972)		(583)
Ending Balance at Mar. 31, 2019	1,286,017	1,282,287	0	548	512,696	(530,760)	1,450,325	(142,682)	(7,840)	3,730
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	20,780	20,780			20,780
Exercise of stock options	1,417	1,417		3	1,414
Shares issued under equity awards (taxes paid related to net share settlement of equity awards), net	(6,393)	(6,393)			(6,393)
Other	(80)	(80)			(80)
Purchase of common stock	(34,561)	(34,561)				(34,561)
Reissuance of treasury stock towards employee stock purchase plan	872	872			(73)	945
Contra equity - indemnification receivable for acquisition related tax liability	1,116	1,116							1,116	0
Net earnings	137,116	137,116					137,116			0
Dividends	(29,705)	(29,705)			756		(30,461)
Other comprehensive income:
Pension funded status adjustment, (net of tax (expense) benefit)	(2,003)	(2,003)						(2,003)
Net unrealized gain (loss) on derivative instruments (net of tax (benefit) expense)	(5,793)	(5,793)						(5,793)
Foreign currency translation adjustment	(64,721)	(64,528)						(64,528)		(193)
Ending Balance at Mar. 31, 2020	1,304,062	1,300,525	0	551	529,100	(564,376)	1,556,980	(215,006)	(6,724)	3,537
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	19,817	19,817			19,817
Exercise of stock options	9,114	9,114		4	9,110
Shares issued under equity awards (taxes paid related to net share settlement of equity awards), net	(5,153)	(5,153)			(5,153)
Other	571	571			571
Reissuance of treasury stock towards employee stock purchase plan	846	846			(49)	895
Contra equity - indemnification receivable for acquisition related tax liability	1,369	1,369							1,369	0
Net earnings	143,374	143,374					143,374			0
Dividends	(29,831)	(29,831)			772		(30,603)
Other comprehensive income:
Pension funded status adjustment, (net of tax (expense) benefit)	1,847	1,847						1,847
Net unrealized gain (loss) on derivative instruments (net of tax (benefit) expense)	6,283	6,283						6,283
Foreign currency translation adjustment	91,277	90,993						90,993		284
Ending Balance at Mar. 31, 2021	$ 1,543,576	$ 1,539,755	$ 0	$ 555	$ 554,168	$ (563,481)	$ 1,669,751	$ (115,883)	$ (5,355)	$ 3,821

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Statement of Stockholders' Equity [Abstract]
Dividends per common share	$ 0.70	$ 0.70	$ 0.70
Net unrealized gain (loss) on derivative instruments, tax (benefit) expense	$ 424	$ 468	$ 120
Tax expense related to unrealized gain (loss) on derivative instruments	$ 1,952	$ (1,793)	$ 1,006

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities
Net earnings	$ 143,374	$ 137,116	$ 160,627
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	94,082	87,344	63,348
Write-off of assets relating to restructuring and other exit charges	10,231	10,986	26,308
Impairment of goodwill	0	39,713	0
Impairment of indefinite-lived intangibles and fixed assets	0	4,549	0
Derivatives not designated in hedging relationships:
Net (gains) losses	(430)	178	1,856
Cash (settlements) proceeds	905	(793)	(1,802)
Provision for doubtful accounts	178	4,821	1,385
Deferred income taxes	(8,994)	(16,486)	(6,456)
Non-cash interest expense	2,072	1,673	1,316
Stock-based compensation	19,817	20,780	22,608
Gain on disposal of property, plant, and equipment	(3,883)	(86)	(258)
Changes in assets and liabilities, net of effects of acquisitions:
Accounts receivable	8,713	26,486	5,974
Inventories	24,176	(9,379)	(46,614)
Prepaid and other current assets	27,292	(17,508)	(20,195)
Other assets	424	3,089	(7,611)
Accounts payable	20,797	(33,490)	9,944
Legal proceedings accrual	0	0	7,258
Accrued expenses	32,357	7,055	(4,937)
Other liabilities	(12,736)	(12,650)	(14,896)
Net cash provided by operating activities	358,375	253,398	197,855
Cash flows from investing activities
Capital expenditures	(70,020)	(101,425)	(70,372)
Purchase of businesses	0	(176,548)	(654,614)
Proceeds from sale of facility	0	720	0
Insurance proceeds relating to property, plant and equipment	4,800	403	0
Proceeds from disposal of property, plant, and equipment	176	2,031	1,103
Net cash used in investing activities	(65,044)	(274,819)	(723,883)
Cash flows from financing activities
Net (repayments) borrowings on short-term debt	(15,934)	(5,325)	37,424
Debt issuance costs	0	(4,607)	(1,393)
Finance lease obligations and other	650	995	368
Option proceeds	9,114	1,417	9,048
Payment of taxes related to net share settlement of equity awards	(5,153)	(6,393)	(3,630)
Purchase of treasury stock	0	(34,561)	(56,436)
Dividends paid to stockholders	(29,812)	(29,705)	(29,743)
Net cash (used in) provided by financing activities	(188,724)	62,683	346,577
Effect of exchange rate changes on cash and cash equivalents	20,222	(13,495)	(43,455)
Net increase (decrease) in cash and cash equivalents	124,829	27,767	(222,906)
Cash and cash equivalents at beginning of year	326,979	299,212	522,118
Cash and cash equivalents at end of year	451,808	326,979	299,212
Non-cash investing and financing activities:
Common stock issued as partial consideration for Alpha acquisition	0	0	93,268
2017 Revolver borrowings
Cash flows from financing activities
Proceeds from borrowings	102,000	386,700	531,100
Repayments of borrowings	(210,000)	(517,700)	(427,600)
2027 Notes
Cash flows from financing activities
Proceeds from borrowings	0	300,000	0
Amended 2017 Term Loan
Cash flows from financing activities
Proceeds from Amended 2017 Term Loan	0	0	299,105
Repayments of Amended 2017 Term Loan	$ (39,589)	$ (28,138)	$ (11,666)

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	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 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 Beginning April 1, 2018, the Company adopted ASC 606, Revenue from Contracts with Customers . Concurrent with the adoption of the new standard, the Company 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 the 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. The Company's typical payment terms are 30 days and sales arrangements do not contain any significant financing component for its customers. 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. 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 Energy Systems batteries, from one to seven years for Motive Power batteries and for a period ranging from one to four years for Specialty transportation 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 Accounts receivable are recorded net of an allowance for expected credit losses. The Company maintains an allowance for credit losses for the expected failure or inability of its customers to make required payments. The Company recognizes the allowance for expected credit losses at inception and reassesses quarterly based on management’s expectation of the asset’s collectability. The allowance is based on multiple factors including historical experience with bad debts, the credit quality of the customer base, the aging of such receivables and current macroeconomic conditions, as well as management’s expectations of conditions in the future. The Company’s allowance for uncollectible accounts receivable is based on management’s assessment of the collectability of assets pooled together with similar risk characteristics. Accounts are written off when management determines the account is uncollectible. Inventories Inventories are stated at the lower of cost or net realizable value. 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. The Company assesses whether goodwill 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 a reporting unit is less than its carrying amount, including goodwill. If based on this qualitative assessment the Company determines it is more likely than not that the fair value of a reporting unit is less than its carrying amount, or if the Company elects not to perform a qualitative assessment, a quantitative assessment is performed by determining the fair value of the Company's reporting units. 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 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, 2021 and 2020. 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. Regarding the GILTI tax rules, 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. 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. Beginning in fiscal 2017 and until fiscal 2020, 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, relative to the shareholder return of a defined peer group. 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 and fiscal 2020, 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 is 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, 2021, 2020 and 2019, the Company had outstanding stock options, restricted stock units, market condition and performance condition-based awards, which could potentially dilute basic earnings per share in the future. Segment Reporting Effective April 1, 2020, the Company's chief operating decision maker, or CODM (the Company's Chief Executive Officer), changed the manner in which he reviews financial information for purposes of assessing business performance and allocating resources, by focusing on the lines of business on a global basis, rather than on geographic basis. As a result of this change, the Company re-evaluated the identification of its operating segments and reportable segments and identified the following as its three new operating segments, based on lines of business: • Energy Systems - uninterruptible power systems, or “UPS” applications for computer and computer-controlled systems, as well as telecommunications systems, switchgear and electrical control systems used in industrial facilities and electric utilities, large-scale energy storage and energy pipelines. Energy Systems also includes highly integrated power solutions and services to broadband, telecom, renewable and industrial customers, as well as thermally managed cabinets and enclosures for electronic equipment and batteries. • Motive Power - power for electric industrial forklifts used in manufacturing, warehousing and other material handling applications, as well as mining equipment, diesel locomotive starting and other rail equipment; and • Specialty - premium starting, lighting and ignition applications in transportation, energy solutions for satellites, military aircraft, submarines, ships and other tactical vehicles, as well as medical and security systems. The new operating segments also represent the Company's reportable segments under ASC 280, Segment Reporting . All prior comparative periods presented have been recast to conform to these changes. Recently Adopted Accounting Pronouncements 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 previous guidance, which considers current information and events

Revenue Recognition

Revenue Recognition	12 Months Ended
	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition The Company's revenues by reportable segments are presented in Note 23. Service revenues for fiscal 2021, 2020 and 2019 amounted to $296,213, $270,704 and $157,236, respectively. 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 definition 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 fiscal 2021, 2020 and 2019 amounted to $155,217, $142,153 and $100,809, respectively. On March 31, 2021, the aggregate transaction price allocated to unsatisfied (or partially unsatisfied) performance obligations was approximately $115,775, of which, the Company estimates that approximately $93,941 will be recognized as revenue in fiscal 2022, $21,011 in fiscal 2023, $774 in fiscal 2024, $49 in fiscal 2025 and $0 in fiscal 2026. 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, 2021, the current and non-current portion of contract liabilities were $15,992 and $2,072, respectively. As of March 31, 2020, the current and non-current portion of contract liabilities were $17,342 and $8,356, respectively. Revenues recognized during fiscal 2021 and fiscal 2020, that were included in the contract liability at the beginning of the year, amounted to $14,064 and $18,697, respectively. Amounts representing work completed and not billed to customers represent contract assets and were $46,451 and $39,048 as of March 31, 2021 and March 31, 2020, 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, 2021, the right of return asset related to the value of inventory anticipated to be returned from customers was $4,271 and refund liability representing amounts estimated to be refunded to customers was $7,475.

Leases

Leases	12 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Leases	Leases The Company leases manufacturing facilities, distribution centers, office space, vehicles and other equipment under non-cancellable leases with initial terms typically ranging from 1 to 17 years. At contract inception, the Company reviews the terms of the arrangement to determine if the contract is or contains a lease. Guidance in Topic 842 is used to evaluate whether the contract has an identified asset; if the Company has the right to obtain substantially all economic benefits from the asset; and if it has the right to direct the use of the underlying asset. When determining if a contract has an identified asset, the Company considers both explicit and implicit assets, and whether the supplier has the right to substitute the asset. When determining if the Company has the right to obtain substantially all economic benefits from the asset, the Company considers the primary outputs of the identified asset throughout the period of use and determines if it receives greater than 90% of those benefits. When determining if it has the right to direct the use of an underlying asset, the Company considers if it has the right to direct how and for what purpose the asset is used throughout the period of use and if it controls the decision-making rights over the asset. Lease terms may include options to extend or terminate the lease. The Company exercises its judgment to determine the term of those leases when extension or termination options are present and include such options in the calculation of the lease term when it is reasonably certain that the Company will exercise those options. The Company has elected to include both lease and non-lease components in the determination of lease payments for all asset classes. Payments made to a lessor for items such as taxes, insurance, common area maintenance, or other costs commonly referred to as executory costs, are also included in lease payments if they are fixed. The fixed portion of these payments are included in the calculation of the lease liability, while any variable portion would be recognized as variable lease expenses, when incurred. Variable payments made to third parties for these, or similar costs, such as utilities, are not included in the calculation of lease payments. Both finance and operating leases are reflected as liabilities on the commencement date of the lease based on the present value of the lease payments to be made over the lease term. As most of the leases do not provide an implicit rate, the Company has exercised judgment in electing the incremental borrowing rate based on the information available when the lease commences to determine the present value of future payments. Right-of-use assets are valued at the initial measurement of the lease liability, plus any initial direct costs or rent prepayments and reduced by any lease incentives and any deferred lease payments. Operating lease expense is recognized on a straight-line basis over the lease term. Finance lease expense includes depreciation, which is recognized on a straight-line basis over the expected life of the leased asset, and interest expense, which is recognized following an effective interest rate method. Short term leases with an initial term of 12 months or less are not presented on the balance sheet and expense is recognized as incurred. The current and non-current portion of operating lease liabilities are reflected in accrued expenses and other liabilities, respectively, on the consolidated balance sheets. The right-of use assets relating to operating and finance leases are reflected in other assets and property, plant and equipment, respectively, on the consolidated balance sheets. The following table presents lease assets and liabilities and their balance sheet classification: Classification As of March 31, 2021 As of March 31, 2020 Operating Leases: Right-of-use assets Other assets $ 62,159 $ 70,045 Operating lease current liabilities Accrued expenses 21,774 21,128 Operating lease non-current liabilities Other liabilities 42,528 51,215 Finance Leases: Right-of-use assets Property, plant, and equipment, net $ 573 $ 540 Finance lease current liabilities Current portion of finance leases 236 162 Finance lease non-current liabilities Finance leases 435 407 The components of lease expense for the fiscal years ended March 31, 2021 and March 31, 2020 were as follows: Classification March 31, 2021 March 31, 2020 Operating Leases: Operating lease cost Operating expenses $ 27,888 $ 28,855 Variable lease cost Operating expenses 7,781 8,238 Short term lease cost Operating expenses 6,675 7,553 Finance Leases: Depreciation Operating expenses $ 221 $ 461 Interest expense Interest expense 33 37 Total $ 42,598 $ 45,144 The following table presents the weighted average lease term and discount rates for leases as of March 31, 2021 and March 31, 2020: March 31, 2021 March 31, 2020 Operating Leases: Weighted average remaining lease term (years) 5.5 years 5.0 years Weighted average discount rate 5.16% 5.17% Finance Leases: Weighted average remaining lease term (years) 3.1 years 3.5 years Weighted average discount rate 4.81% 4.92% The following table presents future payments due under leases reconciled to lease liabilities as of March 31, 2021: Finance Leases Operating Leases Year ended March 31, 2022 $ 264 $ 24,663 2023 218 16,618 2024 159 10,717 2025 48 6,977 2026 26 5,114 Thereafter — 12,997 Total undiscounted lease payments 715 77,086 Present value discount 44 12,784 Lease liability $ 671 $ 64,302 The following table presents supplemental disclosures of cash flow information related to leases for the fiscal years ended March 31, 2021 and March 31, 2020: March 31, 2021 March 31, 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from finance leases $ 33 $ 37 Operating cash flows from operating leases 28,036 28,593 Financing cash flows from finance leases 216 461 Supplemental non-cash information on lease liabilities arising from right-of-use assets: Right-of-use assets obtained in exchange for new finance lease liabilities $ 266 $ — Right-of-use assets obtained in exchange for new operating lease liabilities 14,763 11,902
Leases	Leases The Company leases manufacturing facilities, distribution centers, office space, vehicles and other equipment under non-cancellable leases with initial terms typically ranging from 1 to 17 years. At contract inception, the Company reviews the terms of the arrangement to determine if the contract is or contains a lease. Guidance in Topic 842 is used to evaluate whether the contract has an identified asset; if the Company has the right to obtain substantially all economic benefits from the asset; and if it has the right to direct the use of the underlying asset. When determining if a contract has an identified asset, the Company considers both explicit and implicit assets, and whether the supplier has the right to substitute the asset. When determining if the Company has the right to obtain substantially all economic benefits from the asset, the Company considers the primary outputs of the identified asset throughout the period of use and determines if it receives greater than 90% of those benefits. When determining if it has the right to direct the use of an underlying asset, the Company considers if it has the right to direct how and for what purpose the asset is used throughout the period of use and if it controls the decision-making rights over the asset. Lease terms may include options to extend or terminate the lease. The Company exercises its judgment to determine the term of those leases when extension or termination options are present and include such options in the calculation of the lease term when it is reasonably certain that the Company will exercise those options. The Company has elected to include both lease and non-lease components in the determination of lease payments for all asset classes. Payments made to a lessor for items such as taxes, insurance, common area maintenance, or other costs commonly referred to as executory costs, are also included in lease payments if they are fixed. The fixed portion of these payments are included in the calculation of the lease liability, while any variable portion would be recognized as variable lease expenses, when incurred. Variable payments made to third parties for these, or similar costs, such as utilities, are not included in the calculation of lease payments. Both finance and operating leases are reflected as liabilities on the commencement date of the lease based on the present value of the lease payments to be made over the lease term. As most of the leases do not provide an implicit rate, the Company has exercised judgment in electing the incremental borrowing rate based on the information available when the lease commences to determine the present value of future payments. Right-of-use assets are valued at the initial measurement of the lease liability, plus any initial direct costs or rent prepayments and reduced by any lease incentives and any deferred lease payments. Operating lease expense is recognized on a straight-line basis over the lease term. Finance lease expense includes depreciation, which is recognized on a straight-line basis over the expected life of the leased asset, and interest expense, which is recognized following an effective interest rate method. Short term leases with an initial term of 12 months or less are not presented on the balance sheet and expense is recognized as incurred. The current and non-current portion of operating lease liabilities are reflected in accrued expenses and other liabilities, respectively, on the consolidated balance sheets. The right-of use assets relating to operating and finance leases are reflected in other assets and property, plant and equipment, respectively, on the consolidated balance sheets. The following table presents lease assets and liabilities and their balance sheet classification: Classification As of March 31, 2021 As of March 31, 2020 Operating Leases: Right-of-use assets Other assets $ 62,159 $ 70,045 Operating lease current liabilities Accrued expenses 21,774 21,128 Operating lease non-current liabilities Other liabilities 42,528 51,215 Finance Leases: Right-of-use assets Property, plant, and equipment, net $ 573 $ 540 Finance lease current liabilities Current portion of finance leases 236 162 Finance lease non-current liabilities Finance leases 435 407 The components of lease expense for the fiscal years ended March 31, 2021 and March 31, 2020 were as follows: Classification March 31, 2021 March 31, 2020 Operating Leases: Operating lease cost Operating expenses $ 27,888 $ 28,855 Variable lease cost Operating expenses 7,781 8,238 Short term lease cost Operating expenses 6,675 7,553 Finance Leases: Depreciation Operating expenses $ 221 $ 461 Interest expense Interest expense 33 37 Total $ 42,598 $ 45,144 The following table presents the weighted average lease term and discount rates for leases as of March 31, 2021 and March 31, 2020: March 31, 2021 March 31, 2020 Operating Leases: Weighted average remaining lease term (years) 5.5 years 5.0 years Weighted average discount rate 5.16% 5.17% Finance Leases: Weighted average remaining lease term (years) 3.1 years 3.5 years Weighted average discount rate 4.81% 4.92% The following table presents future payments due under leases reconciled to lease liabilities as of March 31, 2021: Finance Leases Operating Leases Year ended March 31, 2022 $ 264 $ 24,663 2023 218 16,618 2024 159 10,717 2025 48 6,977 2026 26 5,114 Thereafter — 12,997 Total undiscounted lease payments 715 77,086 Present value discount 44 12,784 Lease liability $ 671 $ 64,302 The following table presents supplemental disclosures of cash flow information related to leases for the fiscal years ended March 31, 2021 and March 31, 2020: March 31, 2021 March 31, 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from finance leases $ 33 $ 37 Operating cash flows from operating leases 28,036 28,593 Financing cash flows from finance leases 216 461 Supplemental non-cash information on lease liabilities arising from right-of-use assets: Right-of-use assets obtained in exchange for new finance lease liabilities $ 266 $ — Right-of-use assets obtained in exchange for new operating lease liabilities 14,763 11,902

Acquisitions

Acquisitions	12 Months Ended
	Mar. 31, 2021
Business Combinations [Abstract]
Acquisitions	Acquisitions The Company made no acquisitions in fiscal 2021. Acquisitions made in fiscal 2020 and fiscal 2019 are as follows: NorthStar On September 30, 2019, the Company completed the acquisition of N Holding, AB (“NorthStar”) for $77,777 in cash consideration and the assumption of $107,018 in debt, which was funded using existing cash and credit facilities. NorthStar, through its direct and indirect subsidiaries, manufactures and distributes thin plate pure lead (TPPL) batteries and battery enclosures. NorthStar has two large manufacturing facilities in Springfield, Missouri. The Company acquired tangible and intangible assets, including trademarks, technology, customer relationships and goodwill. Based on valuations performed, trademarks were valued at $6,000, technology at $19,000, customer relationships at $9,000, and goodwill was recorded at $76,784. As a result of the change in operating segments discussed in Note 23, goodwill associated with the acquisition of NorthStar has been allocated to the Energy Systems and Specialty segments on a relative fair value basis. The useful lives of technology were estimated at 10 years, customer relationships were estimated at 15 to 18 years and trademarks were estimated at 5 years. Goodwill deductible for tax purposes is $68,522. During fiscal 2021, the Company finalized the measurement of all provisional amounts recognized in connection with the NorthStar business combination. The purchase accounting adjustments resulted in an increase to goodwill by $2,996 as a result of finalizing income tax accounting. The results of the NorthStar acquisition have been included in the Company’s results of operations from the date of acquisition. Pro forma earnings and earnings per share computations have not been presented as this acquisition is not considered material. Alpha 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 “Alpha 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 “Alpha asset acquisition” and together with the Alpha share purchase, the “Alpha 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 Alpha 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 post - closing from seller of $766) was $742,502. The Company funded the cash portion of the Alpha acquisition with borrowings from the Amended Credit Facility as defined in Note 10. See Note 10 for additional information. The results of operations of Alpha have been included in the Company’s Energy Systems segment. 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 Company finalized the measurement of all provisional amounts recognized for the Alpha business combination in fiscal 2020. The final amounts recognized in connection with the Alpha business combination are in the table below. 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 54,941 Other liabilities 12,642 Total liabilities assumed $ 145,304 Net assets acquired $ 423,274 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 423,274 Goodwill $ 319,228 The following table summarizes the fair value of Alpha's identifiable intangible assets and their respective 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 As of March 31, 2021, goodwill deductible for tax purposes relating to Alpha is $28,525. The following unaudited summary information is presented on a consolidated pro forma basis as if the acquisition had occurred on April 1, 2018: Fiscal year ended March 31, 2019 Net sales $ 3,250,332 Net earnings attributable to EnerSys stockholders 181,915 Net earnings per share attributable to EnerSys stockholders - basic 4.19 Net earnings per share attributable to EnerSys stockholders - assuming dilution 4.12 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, 2018, nor are they indicative of future combined results. The pro forma results for the twelve months of fiscal 2019 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 being excluded in arriving at these pro forma results.

Inventories

Inventories	12 Months Ended
	Mar. 31, 2021
Inventory Disclosure [Abstract]
Inventories	Inventories March 31, 2021 2020 Raw materials $ 147,040 $ 141,906 Work-in-process 97,715 91,520 Finished goods 273,492 286,034 Total $ 518,247 $ 519,460

Property, Plant, and Equipment

Property, Plant, and Equipment	12 Months Ended
	Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Property, Plant, and Equipment	Property, Plant, and Equipment Property, plant, and equipment consist of: March 31, 2021 2020 Land, buildings, and improvements $ 313,031 $ 291,271 Machinery and equipment 822,725 722,955 Construction in progress 60,049 93,921 1,195,805 1,108,147 Less accumulated depreciation (698,749) (628,133) Total $ 497,056 $ 480,014 Depreciation expense for the fiscal years ended March 31, 2021, 2020 and 2019 totaled $60,956, $56,331, and $48,618, respectively. Interest capitalized in connection with major capital expenditures amounted to $1,319, $2,030, and $1,581 for the fiscal years ended March 31, 2021, 2020 and 2019, respectively.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Mar. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Other Intangible Assets Information regarding the Company’s other intangible assets are as follows: March 31, 2021 2020 Gross Accumulated Net Gross Accumulated Net Indefinite-lived intangible assets: Trademarks $ 148,164 $ (953) $ 147,211 $ 147,352 $ (953) $ 146,399 Finite-lived intangible assets: Customer relationships 298,576 (87,308) 211,268 292,155 (64,855) 227,300 Non-compete 2,825 (2,825) — 3,021 (2,817) 204 Technology 97,349 (29,561) 67,788 96,047 (20,349) 75,698 Trademarks 8,012 (3,381) 4,631 8,012 (1,928) 6,084 Licenses 1,196 (1,196) — 1,196 (1,196) — Total $ 556,122 $ (125,224) $ 430,898 $ 547,783 $ (92,098) $ 455,685 The Company’s amortization expense related to finite-lived intangible assets was $33,126, $31,013, and $14,730, for the years ended March 31, 2021, 2020 and 2019, respectively. The expected amortization expense based on the finite-lived intangible assets as of March 31, 2021, is $32,624 in fiscal 2022, $30,399 in fiscal 2023, $27,545 in fiscal 2024, $26,552 in fiscal 2025 and $25,618 in fiscal 2026. Goodwill Concurrent with the change in operating segments effective April 1, 2020, goodwill was reassigned to the affected reporting units that have been identified within each operating segment, using a relative fair value approach outlined in ASC 350, Intangibles - Goodwill and Other . The following table presents the amount of goodwill that has been reassigned to each of the Company's reporting units as of April 1, 2020, using the relative fair value approach, as well as changes in the carrying amount of goodwill by segment during fiscal 2020 and 2021: Energy Systems Motive Power Specialty Americas (2) EMEA Asia (2) Total Balance at April 1, 2019 $ — $ — $ — $ 470,194 $ 143,269 $ 42,936 $ 656,399 Acquisitions during the year — — — 72,056 1,732 — 73,788 Measurement period adjustments — — — (1,390) — — (1,390) Goodwill impairment charge — — — — — (39,713) (39,713) Foreign currency translation adjustment — — — (16,704) (5,221) (3,223) (25,148) Balance at March 31, 2020 — — — 524,156 139,780 — 663,936 Reallocation to new Reporting Units (1) 263,150 308,497 92,289 (524,156) (139,780) — — Balance at April 1, 2020 263,150 308,497 92,289 — — — 663,936 Measurement period adjustments 1,348 — 1,648 — — — 2,996 Foreign currency translation adjustment 15,178 18,558 4,925 — — — 38,661 Balance at March 31, 2021 $ 279,676 $ 327,055 $ 98,862 $ — $ — $ — $ 705,593 (1) Represents the reallocation of goodwill as a result of the Company reorganizing its segments as described in Note 1. (2) Goodwill is net of accumulated impairment charges of $57,845 and $44,892 in the legacy Americas and Asia reporting units, respectively, as of March 31, 2020. Impairment of goodwill, finite and indefinite-lived intangibles Goodwill is tested annually for impairment during the fourth quarter or earlier upon the occurrence of certain events or substantive changes in circumstances that indicate goodwill is more likely than not impaired. The Company did not record any impairment relating to its goodwill and intangible assets during fiscal 2021 and 2019. In the fourth quarter of fiscal 2020, the Company conducted its annual goodwill impairment test which indicated that the fair value of its legacy Asia reporting unit was less than its carrying value. The Company recorded a non-cash charge of $39,713 related to goodwill impairment in Asia under the caption “Impairment of goodwill” in the Consolidated Statements of Income. The Company also recorded a non-cash charge of $4,549 related to impairment of indefinite-lived trademarks in its legacy EMEA reportable segment under the caption “Impairment of indefinite-lived intangibles” in the Consolidated Statements of Income. The key factors contributing to the impairment in Asia was the increasing pressure on organic sales growth that the Company began to experience in fiscal 2019 due to a slowdown in telecom spending in the People's Republic of China (“PRC”) amidst growing trade tensions between the U.S.A and China. The impact of these trade tensions on the Company's ability to capture market share in the PRC accelerated in the second half of the fiscal year. Throughout fiscal 2020, there was a general slowdown in the Chinese economy which was further exacerbated by the outbreak of the COVID -19 pandemic, causing disruption to two of the Company's plants in China in the fourth quarter. Also contributing to the poor performance of the Asia region was a general softening of demand in Australia, that began in fiscal 2019 and continued throughout fiscal 2020. The Company monitored the performance of its Asia reporting unit for interim impairment indicators throughout fiscal 2020, but the emergence of COVID-19 in China in December 2019 coupled with the totality of economic headwinds in the region resulted in the recognition of a goodwill impairment loss in connection with its annual impairment test. During the fourth quarter of fiscal 2020, management completed its evaluation of key inputs used to estimate the fair value of its indefinite-lived trademarks and determined that an impairment charge relating to two of its trademarks in EMEA, that were acquired through legacy acquisitions was appropriate, as it plans to phase out these trademarks.

Prepaid and Other Current Asset

Prepaid and Other Current Assets	12 Months Ended
	Mar. 31, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid and Other Current Assets	Prepaid and Other Current Assets Prepaid and other current assets consist of the following: March 31, 2021 2020 Contract assets $ 46,451 $ 39,048 Prepaid non-income taxes 25,251 23,069 Non-trade receivables 10,925 19,380 Prepaid income taxes 6,562 13,062 Other 28,492 26,034 Total $ 117,681 $ 120,593

Accrued Expenses

Accrued Expenses	12 Months Ended
	Mar. 31, 2021
Payables and Accruals [Abstract]
Accrued Expenses	Accrued Expenses Accrued expenses consist of the following: March 31, 2021 2020 Payroll and benefits $ 92,305 $ 62,131 Accrued selling expenses 47,364 43,292 Hagen exit related accruals 24,593 — Operating lease liabilities 21,774 21,128 Warranty 18,982 27,766 Contract liabilities 15,992 17,342 VAT and other non-income taxes 14,267 14,209 Freight 13,097 14,222 Interest 10,592 11,180 Tax Act - Transition Tax 6,172 6,172 Income taxes payable 5,683 304 Restructuring 2,595 3,325 Pension 1,514 1,350 Other 43,793 49,319 Total $ 318,723 $ 271,740

Debt

Debt	12 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Debt	Debt The following summarizes the Company’s long-term debt as of March 31, 2021 and March 31, 2020: 2021 2020 Principal Unamortized Issuance Costs Principal Unamortized Issuance Costs Senior Notes $ 600,000 $ 5,106 $ 600,000 $ 6,306 Amended Credit Facility, due 2022 376,039 1,315 513,224 2,187 $ 976,039 $ 6,421 $ 1,113,224 $ 8,493 Less: Unamortized issuance costs 6,421 8,493 Long-term debt, net of unamortized issuance costs $ 969,618 $ 1,104,731 The Company's Senior Notes comprise the following: 4.375% Senior Notes due 2027 On December 11, 2019, the Company issued $300,000 in aggregate principal amount of its 4.375% Senior Notes due December 15, 2027 (the “2027 Notes”). Proceeds from this offering, net of debt issuance costs were $296,250 and were utilized to pay down the Amended 2017 Revolver (defined below). The 2027 Notes bear interest at a rate of 4.375% per annum accruing from December 11, 2019. Interest is payable semiannually in arrears on June 15 and December 15 of each year, commencing on June 15, 2020. The 2027 Notes mature on December 15, 2027, unless earlier redeemed or repurchased in full and are unsecured and unsubordinated obligations of the Company. They are fully and unconditionally guaranteed, jointly and severally, by certain of its subsidiaries that are guarantors under the Amended Credit Facility. These guarantees are unsecured and unsubordinated obligations of such guarantors. The Company may redeem, prior to September 15, 2027, all or a portion of the 2027 Notes at a price equal to 100% of the principal amount of the 2027 Notes to be redeemed, plus accrued and unpaid interest and a “make whole” premium to, but excluding, the redemption date. The Company may redeem, on or after September 15, 2027, all or a portion of the 2027 Notes at a price equal to 100% of the principal amount of the 2027 Notes, plus accrued and unpaid interest to, but excluding, the redemption date. If a change of control triggering event occurs, the Company will be required to offer to repurchase the 2027 Notes at a price in cash equal to 101% of the aggregate principal amount of the 2027 Notes, plus accrued and unpaid interest to, but excluding, the date of repurchase. The 2027 Notes rank pari passu with the 2023 Notes. 5.00% Senior Notes due 2023 The 5% Senior Notes due April 30, 2023 (the “2023 Notes”) bear interest at a rate of 5.00% per annum and have an original face value of $300,000. Interest is payable semiannually in arrears on April 30 and October 30 of each year and commenced on October 30, 2015. The 2023 Notes will mature on April 30, 2023, unless earlier redeemed or repurchased in full. The 2023 Notes are unsecured and unsubordinated obligations of the Company. The 2023 Notes are fully and unconditionally guaranteed, jointly and severally, by certain of its subsidiaries that are guarantors under the Amended Credit Facility. These guarantees are unsecured and unsubordinated obligations of such guarantors. 2017 Credit Facility and Subsequent Amendment In fiscal 2018, the Company entered into a credit facility (the “2017 Credit Facility”). The 2017 Credit Facility scheduled to mature on September 30, 2022, initially comprised a $600,000 senior secured revolving credit facility (“2017 Revolver”) and a $150,000 senior secured term loan (“2017 Term Loan”). The Company utilized the borrowings from the 2017 Credit Facility to repay its pre-existing credit facility. In fiscal 2019, 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. Subsequent to the amendment, the quarterly installments payable on the Amended 2017 Term Loan are $5,645 beginning December 31, 2018, $8,468 beginning December 31, 2019 and $11,290 beginning December 31, 2020 with a final payment of $320,000 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 (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 28, 2019, the maximum leverage ratio was increased to 4.00x. On December 29, 2019, the maximum leverage ratio returned to 3.50x. As of March 31, 2021, the Company had $0 outstanding under the Amended 2017 Revolver and $376,039 under the Amended 2017 Term Loan. The current portion of the Amended 2017 Term Loan of $45,579 is classified as long-term debt as the Company expects to refinance the future quarterly payments with revolver borrowings under the Amended Credit Facility. Interest Rates on Long Term Debt The weighted average interest rate on the long term debt at March 31, 2021 and March 31, 2020, was 3.5% and 3.7%, respectively. Interest Paid The Company paid in cash, $36,365, $38,632 and $29,552, net of interest received, for interest during the fiscal years ended March 31, 2021, 2020 and 2019, 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, 2021 and 2020, the Company had $34,153 and $46,544, respectively, of short-term borrowings. The weighted-average interest rate on these borrowings was approximately 2% and 3%, respectively, for fiscal years ended March 31, 2021 and 2020. Letters of Credit As of March 31, 2021 and 2020, the Company had $2,959 and $7,720, respectively, of standby letters of credit. Debt Issuance Costs In fiscal 2020, the Company capitalized $4,607 of debt issuance costs in connection with the issuance of the 2027 Notes. In fiscal 2019, the Company capitalized $1,393 in debt issuance costs and wrote off $483 of unamortized debt issuance costs related to the Amended Credit Facility. Amortization expense, relating to debt issuance costs, included in interest expense was $2,072, $1,673, and $1,316 for the fiscal years ended March 31, 2021, 2020 and 2019, respectively. Debt issuance costs, net of accumulated amortization, totaled $6,421 and $8,493 as of March 31, 2021 and 2020, respectively. Available Lines of Credit As of March 31, 2021 and 2020, the Company had available and undrawn, under all its lines of credit, $697,875 and $693,640, respectively, including $122,303 and $105,946, respectively, of uncommitted lines of credit as of March 31, 2021 and March 31, 2020.

Other Liabilities

Other Liabilities	12 Months Ended
	Mar. 31, 2021
Other Liabilities Disclosure [Abstract]
Other Liabilities	Other Liabilities Other liabilities consist of the following: March 31, 2021 2020 Tax Act - Transition Tax $ 53,045 $ 58,630 Operating lease liabilities 42,528 51,215 Pension 40,450 40,496 Warranty 39,980 35,759 Liability for uncertain tax positions 7,185 8,080 Contract liabilities 2,072 8,356 Other 10,508 11,280 Total $ 195,768 $ 213,816

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments 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, 2021 and March 31, 2020 and the basis for that measurement: Total Fair Value Measurement March 31, 2021 Quoted Price in Significant Significant Lead forward contracts $ (1,980) $ — $ (1,980) $ — Foreign currency forward contracts 424 — 424 — Total derivatives $ (1,556) $ — $ (1,556) $ — Total Fair Value Measurement March 31, 2020 Quoted Price in Significant Significant Lead forward contracts $ (2,433) $ — $ (2,433) $ — Foreign currency forward contracts 1 — 1 — Total derivatives $ (2,432) $ — $ (2,432) $ — 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 10), 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 fair value of the Company's 2027 Notes and 2023 Notes, (collectively, the “Senior Notes”) represent the trading values based upon quoted market prices and are classified as Level 2. The 2027 Notes were trading at approximately 102% and 94% of face value on March 31, 2021 and March 31, 2020, respectively. The 2023 Notes were trading at approximately 105% and 97% of face value on March 31, 2021 and March 31, 2020, respectively. The carrying amounts and estimated fair values of the Company’s derivatives and Senior Notes at March 31, 2021 and 2020 were as follows: March 31, 2021 March 31, 2020 Carrying Fair Value Carrying Fair Value Financial assets: Derivatives (1) $ — $ — $ — $ — Financial liabilities: Senior Notes (2) $ 600,000 $ 621,000 $ 600,000 $ 573,000 Derivatives (1) 1,556 1,556 2,432 2,432 (1) Represents lead and foreign currency forward contracts (see Note 13 for asset and liability positions of the lead and foreign currency forward contracts at March 31, 2021 and March 31, 2020). (2) The fair value amount of the Senior Notes at March 31, 2021 and March 31, 2020 represent the trading value of the instruments. Non-recurring fair value measurements The valuation of goodwill and other intangible assets is based on information and assumptions available to the Company at the time of acquisition, using income and market approaches to determine fair value. The Company tests goodwill and other intangible assets annually for impairment, or when indications of potential impairment exist (see Note 1). Goodwill is tested for impairment by determining the fair value of the Company’s reporting units. The unobservable inputs used to measure the fair value of the reporting units include projected growth rates, profitability, and the risk factor premium added to the discount rate. The remeasurement of the reporting unit fair value is classified as a Level 3 fair value assessment due to the significance of unobservable inputs developed using company-specific information. The inputs used to measure the fair value of other intangible assets were largely unobservable and accordingly were also classified as Level 3. The fair value of trademarks is based on an estimate of the royalties saved that would have been paid to a third party had the Company not owned the trademark. The fair value of other indefinite-lived intangibles was estimated using the income approach, based on cash flow projections of revenue growth rates, taking into consideration industry and market conditions. In connection with the annual impairment testing conducted as of December 30, 2019 for fiscal 2020, two of the Company's indefinite-lived trademarks, that were acquired through legacy acquisitions were recorded at fair value on a non-recurring basis at $1,700 and the remeasurement resulted in an impairment of $4,549. In determining the fair value of these assets, the Company used a royalty rate of 1.25% based on comparable market rates and used a discount rate of 13.0%. These impairment charges relating to goodwill and indefinite-lived trademarks are included under the captions Impairment of goodwill and Impairment of indefinite-lived intangibles in the Consolidated Statements of Income. On November 11, 2020, the Company committed to a plan to substantially close its facility in Hagen, Germany, which produces flooded motive power batteries for forklifts. Management determined that future demand for the motive power batteries produced at this facility was not sufficient, given the conversion from flooded to maintenance free batteries by customers, the existing number of competitors in the market, as well as the near term decline in demand and increased uncertainty from the pandemic. As a result, the Company concluded that the carrying value of the asset group is not recoverable and recorded a write-off of $3,975 of the fixed assets to their estimated fair value of $14,456, which was recognized in the third quarter of fiscal 2021. 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. 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

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Mar. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments 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, 2021 and 2020, the Company has hedged the price to purchase approximately 54.5 million pounds and 35.0 million pounds of lead, respectively, for a total purchase price of $50,567 and $30,078, 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, 2021 and 2020, the Company had entered into a total of $26,033 and $34,008, respectively, of such contracts. In the coming twelve months, the Company anticipates that $597 of pretax gain 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, 2021 and 2020, the notional amount of these contracts was $28,995 and $42,232, 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, 2021 and 2020 Derivatives and Hedging Activities Designated as Cash Flow Hedges Derivatives and Hedging Activities Not Designated as Hedging Instruments March 31, 2021 March 31, 2020 March 31, 2021 March 31, 2020 Prepaid and other current assets: Foreign currency forward contracts $ 524 $ — $ — $ 375 Total assets $ 524 $ — $ — $ 375 Accrued expenses: Lead forward contracts $ 1,980 $ 2,433 $ — $ — Foreign currency forward contracts — 374 100 — Total liabilities $ 1,980 $ 2,807 $ 100 $ — The Effect of Derivative Instruments on the Consolidated Statements of Income For the fiscal year ended March 31, 2021 Derivatives Designated as Cash Flow Hedges Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion) Location of Gain Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion) Lead forward contracts $ 202 Cost of goods sold $ (7,411) Foreign currency forward contracts 130 Cost of goods sold (492) Total $ 332 $ (7,903) Derivatives Not Designated as Hedging Instruments Location of Gain (Loss) Pretax Gain (Loss) Foreign currency forward contracts Other (income) expense, net $ 430 Total $ 430 The Effect of Derivative Instruments on the Consolidated Statements of Income For the fiscal year ended March 31, 2020 Derivatives Designated as Cash Flow Hedges Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion) Location of Gain Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion) Lead forward contracts $ (8,683) Cost of goods sold $ (1,690) Foreign currency forward contracts (54) Cost of goods sold 539 Total $ (8,737) $ (1,151) Derivatives Not Designated as Hedging Instruments Location of Gain (Loss) Pretax Gain (Loss) Foreign currency forward contracts Other (income) expense, net $ (178) Total $ (178) 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 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) Pretax Gain (Loss) Foreign currency forward contracts Other (income) expense, net $ (1,856) Total $ (1,856)

Income Taxes

Income Taxes	12 Months Ended
	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Fiscal year ended March 31, 2021 2020 2019 Current income tax expense Current: Federal $ 12,591 $ 9,185 $ 6,377 State 4,133 2,561 5,027 Foreign 19,031 14,561 16,636 Total current income tax expense 35,755 26,307 28,040 Deferred income tax (benefit) expense Federal 1,495 5,489 (5,031) State 735 741 (669) Foreign (11,224) (22,716) (756) Total deferred income tax (benefit) expense (8,994) (16,486) (6,456) Total income tax expense $ 26,761 $ 9,821 $ 21,584 Earnings before income taxes consists of the following: Fiscal year ended March 31, 2021 2020 2019 United States $ 56,055 $ 36,193 $ 53,339 Foreign 114,080 110,744 128,872 Earnings before income taxes $ 170,135 $ 146,937 $ 182,211 Income taxes paid by the Company for the fiscal years ended March 31, 2021, 2020 and 2019 were $32,002, $48,653 and $53,866, respectively. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) was signed into law in the U.S. to provide certain relief as a result of the COVID-19 pandemic. In addition, governments around the world have enacted or implemented various forms of tax relief measures in response to the economic conditions in the wake of COVID-19. As of March 31, 2021, neither the CARES Act nor changes to income tax laws or regulations in other jurisdictions had a significant impact on the Company’s effective tax rate. 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, 2021 2020 Deferred tax assets: Accounts receivable $ 2,029 $ 1,110 Inventories 8,831 5,010 Net operating loss carryforwards 62,663 44,340 Lease liabilities 15,685 18,168 Accrued expenses 36,775 26,113 Other assets 18,173 19,793 Gross deferred tax assets 144,156 114,534 Less valuation allowance (31,928) (20,951) Total deferred tax assets 112,228 93,583 Deferred tax liabilities: Property, plant and equipment 38,364 30,229 Lease Right-of-use assets 15,685 18,168 Intangible assets 66,743 66,529 Other liabilities 2,636 1,217 Total deferred tax liabilities 123,428 116,143 Net deferred tax liabilities $ (11,200) $ (22,560) The Company has approximately $1,078 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 $235,225 of foreign net operating loss carryforwards, of which $186,816 may be carried forward indefinitely and $48,409 expire between fiscal 2022 and fiscal 2041. In addition, the Company also has approximately $28,955 of state net operating loss carryforwards with expirations between fiscal 2022 and fiscal 2041. The following table sets forth the changes in the Company's valuation allowance for fiscal 2021, 2020 and 2019: Balance at Additions Valuation Allowance Reversal Business Combination Adjustments Other (1) Balance at Fiscal year ended March 31, 2019 $ 15,255 $ 2,978 $ (99) $ 1,157 $ (1,772) $ 17,519 Fiscal year ended March 31, 2020 17,519 7,494 (3,145) (688) (229) 20,951 Fiscal year ended March 31, 2021 20,951 8,437 (2,904) 6,384 (940) 31,928 (1) Includes the impact of currency changes and the expiration of net operating losses for which a full valuation allowance was recorded. As of March 31, 2021 and 2020, the Company had no federal valuation allowance and the valuation allowance associated with the state tax jurisdictions was $686 and $896, respectively. As of March 31, 2021 and 2020, the valuation allowance associated with certain foreign tax jurisdictions was $31,242 and $20,055, respectively. Of the net increase of $11,187, $5,743 was recorded as an increase to tax expense primarily related to deferred tax assets generated in the current year that the Company believes are not more likely than not to be realized. Of the remaining increase, $6,384 is related to purchase accounting from the prior year acquisition offset by $(940) primarily related to foreign currency translation adjustments and 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 2021, 2020 and 2019) to the income tax provision is as follows: Fiscal year ended March 31, 2021 2020 2019 United States statutory income tax expense $ 35,729 $ 30,857 $ 38,264 Increase (decrease) resulting from: Impact of Tax Act — — (13,483) State income taxes, net of federal effect 4,000 2,764 3,285 Nondeductible expenses and other 5,273 5,953 4,378 Legal proceedings charge - European Competition Investigations — — 2,405 Net effect of GILTI, FDII, BEAT 1,985 3,025 2,320 Goodwill impairment - See Note 7 — 10,714 — Effect of foreign operations (20,035) (17,605) (16,763) Valuation allowance 5,533 4,349 2,879 Switzerland Tax Reform (1,883) (26,846) — Research and Development Credit (3,841) (3,390) (1,701) Income tax expense $ 26,761 $ 9,821 $ 21,584 The effective income tax rates for the fiscal years ended March 31, 2021, 2020 and 2019 were 15.7%, 6.7% and 11.9%, 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 increase in fiscal 2021 compared to fiscal 2020 is primarily due to Swiss tax reform, partially offset by the Hagen, Germany exit charges and changes in the mix of earnings among tax jurisdictions. The rate decrease in fiscal 2020 compared to fiscal 2019 is primarily due to changes in mix of earnings among tax jurisdictions, Swiss tax reform, and items related to the Tax Act in fiscal 2019. On May 19, 2019, a public referendum held in Switzerland approved the Federal Act on Tax Reform and AHV (Old-Age and Survivors Insurance) Financing (TRAF) as adopted by the Swiss Federal Parliament on September 28, 2018. The Swiss tax reform measures were effective January 1, 2020. The Company recorded a net deferred tax asset of $22,500 during fiscal 2020, related to the amortizable goodwill and based on further evaluation with the Swiss tax authority, recorded an additional income tax benefit of $1,883 during fiscal 2021. In fiscal 2021, the foreign effective income tax rate on foreign pre-tax income of $114,080 was 6.8%. In fiscal 2020, the foreign effective income tax rate on foreign pre-tax income of $110,744 was (7.4)% and in fiscal 2019, the foreign effective income tax rate on foreign pre-tax income of $128,872 was 12.3%. The rate increase in fiscal 2021 compared to fiscal 2020 is primarily due to Swiss tax reform, partially offset by the Hagen, Germany exit charges and changes in the mix of earnings among tax jurisdictions. The rate decrease in fiscal 2020 compared to fiscal 2019 is primarily due to Swiss tax reform 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, 2021, 2020 and 2019 and was taxed, excluding the impact from the Swiss tax reform, at approximately 8%, 3% and 4%, respectively. The Company has approximately $1,591,000 and $1,376,000 of undistributed earnings of foreign subsidiaries for fiscal years 2021 and 2020, respectively. During fiscal 2021, previously undistributed earnings of certain foreign subsidiaries were no longer considered indefinitely reinvested. As a result, no additional income taxes have been provided as the Company had previously recognized a one-time transition tax on these earnings under the Tax Act. The Company intends to continue to be indefinitely reinvested on the remaining undistributed foreign earnings and outside basis differences and therefore, 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, 2021 2020 2019 Balance at beginning of year $ 7,795 $ 20,165 $ 1,568 Increases related to current year tax positions 346 598 129 Increases related to the Alpha acquisition — 769 7,840 Increases related to prior year tax positions 325 — 11,463 Decreases related to prior tax positions — (11,463) (544) Decreases related to prior year tax positions settled — — (93) Lapse of statute of limitations (1,681) (2,274) (198) Balance at end of year $ 6,785 $ 7,795 $ 20,165 All of the balance of unrecognized tax benefits at March 31, 2021, 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 2010. While the net effect on total unrecognized tax benefits cannot be reasonably estimated, approximately $1,850 is expected to reverse in fiscal 2022 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, 2021 and 2020, the Company had an accrual of $400 and $285, respectively, for interest and penalties.

Retirement Plans

Retirement Plans	12 Months Ended
	Mar. 31, 2021
Retirement Benefits [Abstract]
Retirement Plans	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 2021, 2020 and 2019, includes the following components: United States Plans International Plans Fiscal year ended March 31, Fiscal year ended March 31, 2021 2020 2019 2021 2020 2019 Service cost $ — $ — $ — $ 993 $ 906 $ 997 Interest cost 533 616 631 1,388 1,485 1,831 Expected return on plan assets (272) (448) (514) (1,899) (2,136) (2,151) Amortization and deferral 476 188 184 1,053 910 1,520 Net periodic benefit cost $ 737 $ 356 $ 301 $ 1,535 $ 1,165 $ 2,197 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, 2021 2020 2021 2020 Change in projected benefit obligation Benefit obligation at the beginning of the period $ 18,111 $ 16,647 $ 68,602 $ 75,038 Service cost — — 993 906 Interest cost 533 616 1,388 1,485 Benefits paid, inclusive of plan expenses (802) (1,132) (2,087) (2,262) Plan curtailments and settlements — — (91) (678) Actuarial losses (gains) (36) 1,980 7,761 (3,024) Foreign currency translation adjustment — — 6,686 (2,863) Benefit obligation at the end of the period $ 17,806 $ 18,111 $ 83,252 $ 68,602 Change in plan assets Fair value of plan assets at the beginning of the period $ 12,036 $ 13,763 $ 32,831 $ 36,791 Actual return on plan assets 4,379 (649) 6,272 (1,605) Employer contributions 652 54 1,869 2,098 Benefits paid, inclusive of plan expenses (802) (1,132) (2,087) (2,262) Plan curtailments and settlements — — (91) (482) Foreign currency translation adjustment — — 4,050 (1,709) Fair value of plan assets at the end of the period $ 16,265 $ 12,036 $ 42,844 $ 32,831 Funded status deficit $ (1,541) $ (6,075) $ (40,408) $ (35,771) March 31, 2021 2020 Amounts recognized in the Consolidated Balance Sheets consist of: Non current assets $ 15 $ — Accrued expenses (1,514) (1,350) Other liabilities (40,450) (40,496) Funded status deficit $ (41,949) $ (41,846) 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, 2021, 2020 and 2019: Fiscal year ended March 31, 2021 2020 2019 Amounts recorded in AOCI before taxes: Prior service cost $ (230) $ (258) $ (307) Net loss (25,450) (25,796) (24,051) Net amount recognized $ (25,680) $ (26,054) $ (24,358) Fiscal year ended March 31, 2021 2020 2019 Changes in plan assets and benefit obligations: New prior service cost $ — $ — $ — Net loss (gain) arising during the year (753) 3,793 (99) Effect of exchange rates on amounts included in AOCI 1,909 (804) (1,984) Amounts recognized as a component of net periodic benefit costs: Amortization of prior service cost (46) (43) (45) Amortization or settlement recognition of net loss (1,484) (1,250) (1,659) Total recognized in other comprehensive (income) loss $ (374) $ 1,696 $ (3,787) The amounts included in AOCI as of March 31, 2021 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 $ (46) Net loss (1,163) Net amount expected to be recognized $ (1,209) 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 fiscal year are as follows: United States Plans International Plans March 31, March 31, 2021 2020 2021 2020 All defined benefit plans: Accumulated benefit obligation $ 17,806 $ 18,111 $ 78,360 $ 65,336 Unfunded defined benefit plans: Projected benefit obligation $ — $ — $ 34,932 $ 30,773 Accumulated benefit obligation — — 31,970 28,926 Defined benefit plans with a projected benefit obligation in excess of the fair value of plan assets: Projected benefit obligation $ 17,806 $ 18,111 $ 82,814 $ 68,602 Fair value of plan assets 16,265 12,036 42,390 32,831 Defined benefit plans with an accumulated benefit obligation in excess of the fair value of plan assets: Projected benefit obligation $ 17,806 $ 18,111 $ 82,814 $ 68,602 Accumulated benefit obligation 17,806 18,111 77,928 65,336 Fair value of plan assets 16,265 12,036 42,390 32,831 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, 2021 2020 2019 2021 2020 2019 Discount rate 3.0 % 3.8 % 3.9 % 1.3%-2.3% 1.0%-2.7% 1.4%-3.3% Expected return on plan assets 6.0 6.3 6.3 3.8-5.5 4.3-6.0 4.1-6.0 Rate of compensation increase N/A N/A N/A 2.0-3.5 2.0-4.0 1.8-4.0 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, 2021 2020 2021 2020 Discount rate 3.0 % 3.0 % 0.5%-2.3% 1.3%-2.3% Rate of compensation increase N/A N/A 1.5-4.0 2.0-3.5 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, 2021 and 2020 and the basis for that measurement: March 31, 2021 United States Plans International Plans Total Fair Quoted Price Significant Significant Total Fair Quoted Price Significant Significant Asset category: Cash and cash equivalents $ 1,454 $ 1,454 $ — $ — $ 81 $ 81 $ — $ — Equity securities US (a) 10,435 10,435 — — — — — — International (b) — — — — 28,144 — 28,144 — Fixed income (c) 4,376 4,376 — — 14,619 — 14,619 — Total $ 16,265 $ 16,265 $ — $ — $ 42,844 $ 81 $ 42,763 $ — March 31, 2020 United States Plans International Plans Total Fair Quoted Price Significant Significant Total Quoted Price Significant Significant Asset category: Cash and cash equivalents $ 1,221 $ 1,221 $ — $ — $ 141 $ 141 $ — $ — Equity securities US (a) 6,860 6,860 — — — — — — International (b) — — — — 20,059 — 20,059 — Fixed income (c) 3,955 3,955 — — 12,631 — 12,631 — Total $ 12,036 $ 12,036 $ — $ — $ 32,831 $ 141 $ 32,690 $ — 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 $2,578 to its pension plans in fiscal 2022. Estimated future benefit payments under the Company’s pension plans are as follows: 2022 $ 3,181 2023 3,253 2024 3,172 2025 3,794 2026 4,073 Years 2027-2031 22,308 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, 2021, 2020 and 2019 were $16,460, $15,835 and $12,078, respectively.

Stockholders_ Equity

Stockholders’ Equity	12 Months Ended
	Mar. 31, 2021
Stockholders' Equity and Noncontrolling Interests [Abstract]
Stockholders’ Equity	Stockholders’ Equity 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, 2021 and 2020, 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 demonstrates the change in the number of shares of common stock outstanding during fiscal years ended March 31, 2019, 2020 and 2021, respectively: 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 towards 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 Purchase of treasury stock (581,140) Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes 283,695 Shares outstanding as of March 31, 2020 42,323,305 Purchase of treasury stock — Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes 429,715 Shares outstanding as of March 31, 2021 42,753,020 Treasury Stock The Company did not purchase any shares in fiscal 2021 but purchased 581,140 shares for $34,561 in fiscal 2020. In fiscal 2019, the Company purchased 726,347 shares of its common stock for $56,436. At March 31, 2021 and 2020, the Company held 12,799,790 and 12,791,503 shares as treasury stock, respectively. Treasury Stock Reissuance In fiscal 2019, 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 2021, fiscal 2020 and fiscal 2019, the Company also issued 13,465, 17,410 and 3,256 shares out of its treasury stock, respectively, valued at $62.55 per share, on a 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 Before Reclassifications Amount Reclassified from AOCI Ending March 31, 2021 Pension funded status adjustment $ (22,794) $ 680 $ 1,167 $ (20,947) Net unrealized gain (loss) on derivative instruments (5,923) 250 6,033 360 Foreign currency translation adjustment (186,289) 90,993 — (95,296) Accumulated other comprehensive loss $ (215,006) $ 91,923 $ 7,200 $ (115,883) March 31, 2020 Pension funded status adjustment $ (20,791) $ (2,819) $ 816 $ (22,794) Net unrealized gain (loss) on derivative instruments (130) (6,672) 879 (5,923) Foreign currency translation adjustment (121,761) (64,528) — (186,289) Accumulated other comprehensive loss $ (142,682) $ (74,019) $ 1,695 $ (215,006) 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) The following table presents reclassifications from AOCI during the twelve months ended March 31, 2021: 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 $ 7,903 Cost of goods sold Tax benefit (1,870) Net unrealized loss on derivative instruments, net of tax $ 6,033 Defined benefit pension costs: Prior service costs and deferrals $ 1,529 Net periodic benefit cost, included in other (income) expense, net - See Note 15 Tax benefit (362) Net periodic benefit cost, net of tax $ 1,167 The following table presents reclassifications from AOCI during the twelve months ended March 31, 2020: 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 $ 1,151 Cost of goods sold Tax benefit (272) Net unrealized loss on derivative instruments, net of tax $ 879 Defined benefit pension costs: Prior service costs and deferrals $ 1,098 Net periodic benefit cost, included in other (income) expense, net - See Note 15 Tax benefit (282) Net periodic benefit cost, net of tax $ 816 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 15 Tax benefit (331) Net periodic benefit cost, net of tax $ 1,373

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation As of March 31, 2021, 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 condition-based on total shareholder return (“TSR”) and performance condition-based share units (“PSU”) 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, 2021, 3,206,045 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 2021, the Company granted to management and other key employees 295,068 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 $3,514, with a related tax benefit of $368 for fiscal 2021, $2,996 with a related tax benefit of $565 for fiscal 2020 and $3,251 with a related tax benefit of $634 for fiscal 2019. For purposes of determining the fair value of stock options granted, the Company used a Black-Scholes Model with the following assumptions: 2021 2020 2019 Risk-free interest rate 0.39 % 1.52 % 2.77 % Dividend yield 0.93 % 1.21 % 0.93 % Expected life (years) 6 6 6 Volatility 37.2 % 29.1 % 26.8 % The following table summarizes the Company’s stock option activity in the years indicated: Number of Weighted- Weighted- Aggregate 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 — Expired — — — Options outstanding as of March 31, 2019 554,906 8.0 $ 72.31 $ 1,040 Granted 284,109 57.75 — Exercised (24,826) 57.60 383 Forfeited (22,607) 72.19 88 Expired — — — Options outstanding as of March 31, 2020 791,582 7.8 $ 67.55 $ — Granted 295,068 79.62 — Exercised (247,975) 66.11 6,382 Forfeited (34,854) 69.20 290 Expired (4,320) 80.25 — Options outstanding as of March 31, 2021 799,501 7.8 $ 72.31 $ 14,781 Options exercisable as of March 31, 2021 291,440 6.1 $ 73.25 $ 5,114 Options vested and expected to vest, as of March 31, 2021 782,935 7.8 $ 72.28 $ 14,497 The following table summarizes information regarding stock options outstanding as of March 31, 2021: Range of Exercise Prices Number of Weighted- Weighted- $57.60-$60.00 231,025 7.9 $ 57.73 $60.01-$70.00 56,530 3.9 $ 68.78 $70.01-$83.14 511,946 8.2 $ 79.28 799,501 7.8 $ 72.31 Restricted Stock Units, Market and Performance-condition based Awards Non-Employee Directors In fiscal 2021, the Company granted to non-employee directors 39,726 deferred restricted stock units (“DSU”) at the fair value of $39.93 per restricted stock unit at the date of grant. In fiscal 2020, such grants amounted to 40,462 restricted stock units at the fair value of $39.74 per restricted stock unit at the date of grant and in fiscal 2019, such grants amounted to 35,065 restricted stock units at the fair value of $46.30 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. The Company also granted to non-employee directors, during fiscal 2021, fiscal 2020 and 2019, 1,435, 1,147 and 1,441 restricted stock units, respectively, at fair values of $71.53, $58.05 and $75.32, respectively, under the deferred compensation plan for non-employee directors. Employees In fiscal 2021, the Company granted to management and other key employees 283,101 restricted stock units that vest ratably over four years from the date of grant, at the fair value of $75.39 per restricted stock unit. In fiscal 2020, the Company granted to management and other key employees 301,321 restricted stock units that vest ratably over four years from the date of grant at the fair value of $57.75 per restricted stock unit, 62,512 performance condition-based share units (“PSU”) at the fair value of $50.69 and 51,063 market condition-based share units (“TSR”) at a weighted average fair value of $62.05 per unit at the date of grant, that cliff vest three years from the date of grant. 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 a fair value of $75.17 per restricted stock unit, 45,883 PSUs at the fair value of $68.48 and 36,646 TSRs at a weighted average fair value of $86.23 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 2020 and 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 2020 and fiscal 2019, the Company used a Monte Carlo Simulation with the following assumptions: 2020 2019 Risk-free interest rate 1.50 % 2.66 % Dividend yield — % — % Expected life (years) 3 3 Volatility 34.39 % 26.41 % 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 2021 is presented below: Restricted Stock Units (RSU) Market condition-based Share Units (TSR) Performance condition-based Share Units (PSU) Number of Weighted- Number of Weighted- Number of Weighted- Non-vested awards as of March 31, 2020 880,335 $ 55.61 208,720 $ 80.78 101,130 $ 57.49 Granted 324,262 71.53 37 79.51 — — Stock dividend 8,125 57.69 1,165 83.15 917 57.52 Performance factor — — — — — — Vested (279,995) 58.01 (65,096) 71.17 — — Forfeitures (52,443) 68.94 (18,866) 98.88 (3,701) 56.04 Non-vested awards as of March 31, 2021 880,284 $ 60.07 125,960 $ 83.48 98,346 $ 57.55 The Company recognized stock-based compensation expense relating to restricted stock units, TSRs and PSUs of $16,303, with a related tax benefit of $2,121 for fiscal 2021, $17,784, with a related tax benefit of $2,544 for fiscal 2020 and $19,357, with a related tax benefit of $3,085 for fiscal 2019. All Award Plans As of March 31, 2021, unrecognized compensation expense associated with the non-vested equity awards outstanding was $49,054 and is expected to be recognized over a weighted-average period of 29 months.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share 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, 2021 2020 2019 Net earnings attributable to EnerSys stockholders $ 143,374 $ 137,116 $ 160,239 Weighted-average number of common shares outstanding: Basic 42,548,449 42,411,834 42,335,023 Dilutive effect of: Common shares from exercise and lapse of equity awards, net of shares assumed reacquired 675,954 484,941 673,929 Diluted weighted-average number of common shares outstanding 43,224,403 42,896,775 43,008,952 Basic earnings per common share attributable to EnerSys stockholders $ 3.37 $ 3.23 $ 3.79 Diluted earnings per common share attributable to EnerSys stockholders $ 3.32 $ 3.20 $ 3.73 Anti-dilutive equity awards not included in diluted weighted-average common shares 281,483 698,546 355,728

Commitments, Contingencies and

Commitments, Contingencies and Litigation	12 Months Ended
	Mar. 31, 2021
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. With respect to the Belgian regulatory matter, during fiscal 2019, the Company paid $2,402 towards certain aspects related to this matter, which were concluded in fiscal 2021. As of March 31, 2021 and March 31, 2020, the Company did not have a reserve balance related to these matters. 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. 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 believes that it has adequate reserves to satisfy its environmental liabilities. Collective Bargaining At March 31, 2021, the Company had approximately 11,100 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 11% of the total workforce. The average term of these agreements is 2 years, with the longest term being 3.5 years. The Company considers its employee relations to be good and did not experience any significant labor unrest or disruption of production during fiscal 2021. 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 13 - 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 E

Restructuring Plans and Other Exit Charges	12 Months Ended
	Mar. 31, 2021
Restructuring and Related Activities [Abstract]
Restructuring, Exit and Other Charges	Restructuring, Exit and Other Charges Restructuring Programs The Company had committed to various restructuring plans aimed at improving operational efficiencies across its lines of business. A substantial portion of these programs are complete, with an estimated $7,424 remaining to be incurred by the end of fiscal 2022, mainly relating to programs that were started in fiscal 2021, the details of which are as follows: During fiscal 2021, the Company announced restructuring programs in the Energy Systems segment relating to its recent acquisitions of Alpha and NorthStar, as part of its targeted synergy plans. The Company also announced a restructuring program to improve global operational efficiencies in its Motive Power segment. The charges, in both segments were primarily cash charges relating to severance payments and amounted to $3,187 to approximately 47 employees in the Energy Systems segment and $4,012 to approximately 32 employees in the Motive Power segment. In addition there was a $169 charge related to the Specialty segment. During fiscal 2020, the Company announced restructuring programs to improve efficiencies across all its lines of business. The charges were primarily severance payments to approximately 160 employees. The Company completed these actions in fiscal 2021. Restructuring and exit charges for fiscal 2021, 2020 and 2019 by reportable segments are as follows: Fiscal year ended March 31, 2021 Energy Systems Motive Power Specialty Total Restructuring charges $ 3,187 $ 4,012 $ 169 $ 7,368 Exit charges — 32,786 220 33,006 Restructuring and other exit charges $ 3,187 $ 36,798 $ 389 $ 40,374 Fiscal year ended March 31, 2020 Energy Systems Motive Power Specialty Total Restructuring charges $ 6,808 $ 1,860 $ 2,318 $ 10,986 Exit charges 526 5,541 3,713 9,780 Restructuring and other exit charges $ 7,334 $ 7,401 $ 6,031 $ 20,766 Fiscal year ended March 31, 2019 Energy Systems Motive Power Specialty Total Restructuring charges $ 5,115 $ 4,795 $ 713 $ 10,623 Exit charges 5,477 957 17,652 24,086 Restructuring and other exit charges $ 10,592 $ 5,752 $ 18,365 $ 34,709 A roll-forward of the restructuring reserve is as follows: Employee Other Total 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 Accrued 10,395 402 10,797 Costs incurred (9,179) (995) (10,174) Foreign currency impact and other (247) (3) (250) Balance at March 31, 2020 $ 3,325 $ — $ 3,325 Accrued 6,537 831 7,368 Costs incurred (7,550) (831) (8,381) Foreign currency impact and other 283 — 283 Balance at March 31, 2021 $ 2,595 $ — $ 2,595 Exit Charges Fiscal 2021 Programs Hagen, Germany On November 10, 2020, the EnerSys’ Board of Directors approved a plan to substantially close its facility in Hagen, Germany, which produces flooded motive power batteries for forklifts. Management determined that future demand for the motive power batteries produced at this facility was not sufficient, given the conversion from flooded to maintenance free batteries by customers, the existing number of competitors in the market, as well as the near term decline in demand and increased uncertainty from the pandemic. The Company plans to retain the facility with limited sales, service and administrative functions along with related personnel for the foreseeable future. The Company currently estimates that the total charges for these actions will amount to approximately $60,000, the majority of which are expected to be recorded by the end of calendar 2021. Cash charges of approximately $40,000 are primarily for employee severance related payments, but also include payments for cleanup related to the facility, contractual releases and legal expenses. Non-cash charges from inventory and equipment write-offs are estimated to be $20,000. These actions will result in the reduction of approximately 200 employees. During fiscal 2021, the Company recorded cash charges relating to severance of $23,331 and non-cash charges of $7,946 primarily relating to fixed asset write-offs. Vijayawada, India During fiscal 2021, the Company committed to a plan to close its facility in Vijayawada, India to align with its strategic vision for the new line of business structure and footprint and recorded exit charges of $1,509, primarily relating to asset write-offs. Targovishte, Bulgaria 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. Of the estimated total charges of $26,000 for this plan, the Company had recorded charges amounting to $20,242 in fiscal 2019, relating to severance and inventory and fixed asset write-offs and an additional $5,123 relating to cash and non-cash charges during fiscal 2020. During fiscal 2021, in keeping with its strategy of exiting the manufacture of batteries for diesel-electric submarines, the Company completed further actions which resulted in $220 relating to cash and non-cash charges. Fiscal 2020 Programs During fiscal 2020, in keeping with its strategy of exiting the manufacture of batteries for diesel-electric submarines, the Company also sold certain licenses and assets for $2,031 and recorded a net gain of $892, which were reported as other exit charges in the Specialty segment. During fiscal 2020, the Company also wrote off $5,441 of assets at its Kentucky and Tennessee Motive Power plants, as a result of its strategic product mix shift from traditional flooded batteries to maintenance free lead acid and lithium batteries. Fiscal 2019 Programs 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, as part of the aforementioned program to convert its India operations from mainly reserve power production to motive power production, 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 noncash write-off related to reserve power fixed assets in restructuring charges. Richmond, Kentucky Plant Fire During fiscal 2021, the Company settled its claims with its insurance carrier relating to the fire that broke out in the battery formation area of the Company's Richmond, Kentucky motive power production facility in fiscal 2020. The total claims, for both property and business interruption of $46,117 were received through March 31, 2021. The final settlement of insurance recoveries and finalization of costs related to the replacement of property, plant and equipment, resulted in a net gain of $4,397, which was recorded as a reduction to operating expenses in the Consolidated Statements of Income. The details of charges and recoveries for fiscal 2021 and fiscal 2020 are as follows: In fiscal 2020, the Company recorded as a receivable, $17,037, consisting of write-offs for damages caused to its fixed assets and inventories, as well as for cleanup, asset replacement and other ancillary activities directly associated with the fire and received $12,000 related to its initial claims. During fiscal 2021, the Company recorded an additional $16,580 as a receivable for cleanup and received $21,617 from the insurance carrier.

Warranty

Warranty	12 Months Ended
	Mar. 31, 2021
Guarantees [Abstract]
Warranty	Warranty The Company provides for estimated product warranty expenses when 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, costs of claims may ultimately differ from amounts provided. An analysis of changes in the liability for product warranties is as follows: Fiscal year ended March 31, 2021 2020 2019 Balance at beginning of year $ 63,525 $ 54,568 $ 50,602 Current year provisions 27,645 27,622 23,679 Costs incurred (34,346) (25,778) (25,053) Warranty reserves of acquired businesses — 6,995 7,535 Foreign currency translation adjustment 2,138 118 (2,195) Balance at end of year $ 58,962 $ 63,525 $ 54,568

Other (Income) Expense, Net

Other (Income) Expense, Net	12 Months Ended
	Mar. 31, 2021
Other Income and Expenses [Abstract]
Other (Income) Expense, Net	Other (Income) Expense, Net Other (income) expense, net consists of the following: Fiscal year ended March 31, 2021 2020 2019 Foreign exchange transaction losses (gains) $ 6,696 $ 264 $ (3,044) Non-service components of pension expense 1,279 615 1,502 Other (171) (1,294) 928 Total $ 7,804 $ (415) $ (614)

Business Segments

Business Segments	12 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Business Segments	Business Segments Effective April 1, 2020, the Company's chief operating decision maker, or CODM (the Company's Chief Executive Officer), changed the manner in which he reviews financial information for purposes of assessing business performance and allocating resources, by focusing on the lines of business on a global basis, rather than on geographic basis. As a result of this change, the Company re-evaluated the identification of its operating segments and reportable segments and identified the following as its three new operating segments, based on lines of business: • Energy Systems - uninterruptible power systems, or “UPS” applications for computer and computer-controlled systems, as well as telecommunications systems, switchgear and electrical control systems used in industrial facilities and electric utilities, large-scale energy storage and energy pipelines. Energy Systems also includes highly integrated power solutions and services to broadband, telecom, renewable and industrial customers, as well as thermally managed cabinets and enclosures for electronic equipment and batteries. • Motive Power - power for electric industrial forklifts used in manufacturing, warehousing and other material handling applications, as well as mining equipment, diesel locomotive starting and other rail equipment; and • Specialty - premium starting, lighting and ignition applications in transportation, energy solutions for satellites, military aircraft, submarines, ships and other tactical vehicles, as well as medical and security systems. The new operating segments also represent the Company's reportable segments under ASC 280, Segment Reporting . All prior comparative periods presented have been recast to conform to these changes. Summarized financial information related to the Company’s reportable segments at March 31, 2021, 2020 and 2019 and for each of the fiscal years then ended is shown below. Fiscal year ended March 31, 2021 2020 2019 Net sales by segment to unaffiliated customers Energy Systems $ 1,380,278 $ 1,357,475 $ 1,086,279 Motive Power 1,163,710 1,348,193 1,391,844 Specialty 433,944 382,200 329,894 Total net sales $ 2,977,932 $ 3,087,868 $ 2,808,017 Operating earnings by segment Energy Systems $ 67,060 $ 67,809 $ 45,164 Motive Power 143,541 146,814 172,749 Specialty 46,148 42,454 44,077 Inventory step up to fair value relating to acquisitions - Energy Systems — (304) (7,789) Inventory step up to fair value relating to acquisitions - Specialty — (1,550) (2,590) Restructuring and other exit charges - Energy Systems (3,187) (7,284) (10,593) Restructuring and other exit charges - Motive Power (36,798) (2,021) (5,751) Restructuring and other exit charges - Specialty (389) (6,020) (18,365) Impairment of goodwill (3) — (39,713) — Impairment of indefinite-lived intangibles (3) — (4,549) — Fixed asset write-off relating to exit activities and other - Energy Systems — (50) — Fixed asset write-off relating to exit activities and other - Motive Power — (5,380) — Fixed asset write-off relating to exit activities - Specialty — (11) — Legal proceedings charge, net - Energy Systems — — (4,363) Legal proceedings charge, net - Motive Power — — (74) Total operating earnings (2) $ 216,375 $ 190,195 $ 212,465 Capital Expenditures Energy Systems $ 34,826 $ 40,768 $ 24,333 Motive Power 14,154 22,285 26,112 Specialty 21,040 38,372 19,927 Total $ 70,020 $ 101,425 $ 70,372 Depreciation and Amortization Energy Systems $ 57,864 $ 53,793 $ 32,052 Motive Power 21,706 20,900 20,725 Specialty 14,512 12,651 10,571 Total $ 94,082 $ 87,344 $ 63,348 (1) Reportable segments do not record inter-segment revenues and accordingly there are none to report. (2) The Company does not allocate interest expense or other (income) expense, net, to the reportable segments. (3) The impairment of goodwill and indefinite-lived intangibles in fiscal 2020 related to the Company's legacy reportable segments as discussed in Note 7. The Company's property, plant and equipment by reportable segments as of March 31, 2021 and 2020 are as follows: Property, plant and equipment, net March 31, 2021 March 31, 2020 Energy Systems $ 224,513 $ 182,122 Motive Power 152,468 153,438 Specialty 120,075 144,454 Total $ 497,056 $ 480,014 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 59.8%, 58.1% and 48.5% for fiscal years ended March 31, 2021, 2020 and 2019, respectively. Property, plant and equipment, net, attributable to the United States as of March 31, 2021 and 2020, were $291,578 and $277,358, 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 (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Mar. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	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 2021 ended on July 5, 2020, October 4, 2020, January 3, 2021, and March 31, 2021, respectively. The four quarters in fiscal 2020 ended on June 30, 2019, September 29, 2019, December 29, 2019, and March 31, 2020, respectively. 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Fiscal Year Fiscal year ended March 31, 2021 Net sales $ 704,924 $ 708,402 $ 751,067 $ 813,539 $ 2,977,932 Gross profit (1) 174,977 177,560 189,312 197,301 739,150 Operating earnings (2)(3) 53,220 55,415 56,071 51,669 216,375 Net earnings (4) 35,183 35,731 38,624 33,836 143,374 Net earnings attributable to EnerSys stockholders 35,183 35,731 38,624 33,836 143,374 Net earnings per common share attributable to EnerSys stockholders—basic $ 0.83 $ 0.84 $ 0.91 $ 0.79 $ 3.37 Net earnings per common share attributable to EnerSys stockholders—diluted $ 0.82 $ 0.83 $ 0.89 $ 0.78 $ 3.32 Fiscal year ended March 31, 2020 Net sales $ 780,230 $ 762,137 $ 763,698 $ 781,803 $ 3,087,868 Gross profit (5)(6) 201,512 197,317 185,241 200,796 784,866 Operating earnings (7)(8) 68,336 58,710 43,084 20,065 190,195 Net earnings (loss) (9) 48,636 62,698 27,305 (1,523) 137,116 Net earnings (loss) attributable to EnerSys stockholders 48,636 62,698 27,305 (1,523) 137,116 Net earnings (loss) per common share attributable to EnerSys stockholders—basic $ 1.14 $ 1.48 $ 0.65 $ (0.04) $ 3.23 Net earnings (loss) per common share attributable to EnerSys stockholders—diluted $ 1.13 $ 1.47 $ 0.64 $ (0.04) $ 3.20 (1) Included in Gross profit were receipts for business interruption relating to the Richmond, Kentucky motive power production facility, of $3,700, $1,456 and $2,344 for the first, second, and third quarters of fiscal 2021, respectively. (2) Also included in Operating earnings was a net gain of $4,397, recorded in the third quarter of fiscal 2021, relating to the final settlement of insurance recoveries and finalization of costs related to the replacement of property, plant and equipment of the aforementioned claim. (3) Included in Operating earnings were restructuring and other exit charges of $1,387, $3,119, $15,196 and $20,672 for the first, second, third and fourth quarters of fiscal 2021, respectively. (4) Included in net earnings was a tax benefit of $1,883 for the first quarter of fiscal 2021, on account of the Swiss tax reform. (5) Included in Gross profit were inventory adjustment relating to the inventory step up to fair value relating to the NorthStar acquisition of $3,845 and $(1,991) in the third and fourth quarter of fiscal 2020, respectively. (6) Included in Gross profit were receipts for business interruption relating to the Richmond, Kentucky motive power production facility, of $5,000 in the fourth quarter of fiscal 2020. (7) Included in Operating earnings were restructuring and other exit charges of $2,372, $6,282, $9,417 and $2,695 for the first, second, third and fourth quarters of fiscal 2020, respectively. (8) Included in Operating earnings for the fourth quarter of fiscal 2020 were charges relating to the impairment of goodwill for $39,713 and other indefinite-lived intangibles for $4,549.

Subsequent Events

Subsequent Events	12 Months Ended
	Mar. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsOn May 20, 2021, the Board of Directors approved a quarterly cash dividend of $0.175 per share of common stock to be paid on June 25, 2021, to stockholders of record as of June 11, 2021.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Description of Business	Description of BusinessEnerSys (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.
Principles of Consolidation	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	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 Recognition Beginning April 1, 2018, the Company adopted ASC 606, Revenue from Contracts with Customers . Concurrent with the adoption of the new standard, the Company 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 the 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. The Company's typical payment terms are 30 days and sales arrangements do not contain any significant financing component for its customers. 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. 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	WarrantiesThe Company’s products are warranted for a period ranging from one to twenty years for Energy Systems batteries, from one to seven years for Motive Power batteries and for a period ranging from one to four years for Specialty transportation 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 Cash and cash equivalents include all highly liquid investments with an original maturity of three months or less when purchased.
Concentration of Credit Risk	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	Accounts Receivable Accounts receivable are recorded net of an allowance for expected credit losses. The Company maintains an allowance for credit losses for the expected failure or inability of its customers to make required payments. The Company recognizes the allowance for expected credit losses at inception and reassesses quarterly based on management’s expectation of the asset’s collectability. The allowance is based on multiple factors including historical experience with bad debts, the credit quality of the customer base, the aging of such receivables and current macroeconomic conditions, as well as management’s expectations of conditions in the future. The Company’s allowance for uncollectible accounts receivable is based on management’s assessment of the collectability of assets pooled together with similar risk characteristics. Accounts are written off when management determines the account is uncollectible.
Inventories	Inventories Inventories are stated at the lower of cost or net realizable value. 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 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	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 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. The Company assesses whether goodwill 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 a reporting unit is less than its carrying amount, including goodwill. If based on this qualitative assessment the Company determines it is more likely than not that the fair value of a reporting unit is less than its carrying amount, or if the Company elects not to perform a qualitative assessment, a quantitative assessment is performed by determining the fair value of the Company's reporting units. 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 continually evaluates the reasonableness of the useful lives of these assets.
Impairment of Long-Lived 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	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	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, 2021 and 2020. The Company does not have any credit-related contingent features associated with its derivative instruments.
Fair Value of Financial 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	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	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	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. Beginning in fiscal 2017 and until fiscal 2020, 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, relative to the shareholder return of a defined peer group. 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 and fiscal 2020, 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 is 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	Earnings Per ShareBasic 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, 2021, 2020 and 2019, the Company had outstanding stock options, restricted stock units, market condition and performance condition-based awards, which could potentially dilute basic earnings per share in the future.
Segment Reporting	Segment Reporting Effective April 1, 2020, the Company's chief operating decision maker, or CODM (the Company's Chief Executive Officer), changed the manner in which he reviews financial information for purposes of assessing business performance and allocating resources, by focusing on the lines of business on a global basis, rather than on geographic basis. As a result of this change, the Company re-evaluated the identification of its operating segments and reportable segments and identified the following as its three new operating segments, based on lines of business: • Energy Systems - uninterruptible power systems, or “UPS” applications for computer and computer-controlled systems, as well as telecommunications systems, switchgear and electrical control systems used in industrial facilities and electric utilities, large-scale energy storage and energy pipelines. Energy Systems also includes highly integrated power solutions and services to broadband, telecom, renewable and industrial customers, as well as thermally managed cabinets and enclosures for electronic equipment and batteries. • Motive Power - power for electric industrial forklifts used in manufacturing, warehousing and other material handling applications, as well as mining equipment, diesel locomotive starting and other rail equipment; and • Specialty - premium starting, lighting and ignition applications in transportation, energy solutions for satellites, military aircraft, submarines, ships and other tactical vehicles, as well as medical and security systems. The new operating segments also represent the Company's reportable segments under ASC 280, Segment Reporting . All prior comparative periods presented have been recast to conform to these changes.
Recently Adopted Accounting Pronouncements and Accounting Pronouncements Issued But Not Adopted as of March 31, 2021	Recently Adopted Accounting Pronouncements 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 previous 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 adopted the standard effective April 1, 2020 and the adoption did not have a material impact on the Company's operating results, financial position or cash flows. The Company estimates the allowance for credit losses in relation to accounts receivable based on relevant qualitative and quantitative information about historical events, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported accounts receivable. Subsequent to April 1, 2020, accounts receivable are recorded at amortized cost less an allowance for expected credit losses. The Company maintains an allowance for credit losses for the expected failure or inability of its customers to make required payments. The Company recognizes the allowance for expected credit losses at inception and reassesses quarterly, based on management’s expectation of the asset’s collectability. The allowance is based on multiple factors including historical experience with bad debts, the credit quality of the customer base, the aging of such receivables and current macroeconomic conditions, as well as management’s expectations of conditions in the future. The Company’s allowance for uncollectible accounts receivable is based on management’s assessment of the collectability of assets pooled together with similar risk characteristics. The Company then adjusts the historical credit loss percentage by current and forecasted economic conditions. The Company then includes a baseline credit loss percentage into the historical credit loss percentage for each aging category to reflect the potential impact of the current and economic conditions. Such a baseline calculation will be adjusted further if changes in the economic environment impacts the Company's expectation for future credit losses. The following table sets forth the changes in the Company's allowance for doubtful accounts: Balance at Beginning of Period Provision Write-offs, net of Recoveries and Other Balance at Fiscal year ended March 31, 2019 $ 12,643 $ 1,385 $ (3,215) $ 10,813 Fiscal year ended March 31, 2020 10,813 4,821 (388) 15,246 Fiscal year ended March 31, 2021 15,246 178 (2,432) 12,992 In March 2020, the FASB issued ASU 2020-04, “Reference Rate Reform (Topic 848)”: Facilitation of the Effects of Reference Rate Reform on Financial Reporting, which provides temporary optional expedients to ease the financial reporting burdens of the expected market transition from London Interbank Offered Rate (LIBOR) to an alternative reference rate such as Secured Overnight Financing Rate (SOFR). The amendments in this ASU were effective immediately and may be applied to impacted contracts and hedges prospectively through December 31, 2022. The adoption of the ASU had no impact on the Company’s Consolidated Financial Statements for the period ended March 31, 2021. Accounting Pronouncements Issued But Not Adopted as of March 31, 2021 In December 2019, the FASB issued ASU No. 2019-12, “Income Taxes (Topic 740)”: Simplifying the Accounting for Income Taxes, which is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. The guidance is effective for fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. The adoption is not expected to have a material impact on its consolidated financial statements.
Use of Estimates	Use of EstimatesThe 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.

Accounting Policies (Tables)

Accounting Policies (Tables)	12 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable	The following table sets forth the changes in the Company's allowance for doubtful accounts: Balance at Beginning of Period Provision Write-offs, net of Recoveries and Other Balance at Fiscal year ended March 31, 2019 $ 12,643 $ 1,385 $ (3,215) $ 10,813 Fiscal year ended March 31, 2020 10,813 4,821 (388) 15,246 Fiscal year ended March 31, 2021 15,246 178 (2,432) 12,992

Leases (Tables)

Leases (Tables)	12 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Supplemental Balance Sheet Information Related to Leases	The following table presents lease assets and liabilities and their balance sheet classification: Classification As of March 31, 2021 As of March 31, 2020 Operating Leases: Right-of-use assets Other assets $ 62,159 $ 70,045 Operating lease current liabilities Accrued expenses 21,774 21,128 Operating lease non-current liabilities Other liabilities 42,528 51,215 Finance Leases: Right-of-use assets Property, plant, and equipment, net $ 573 $ 540 Finance lease current liabilities Current portion of finance leases 236 162 Finance lease non-current liabilities Finance leases 435 407
Components of Lease Expense	The components of lease expense for the fiscal years ended March 31, 2021 and March 31, 2020 were as follows: Classification March 31, 2021 March 31, 2020 Operating Leases: Operating lease cost Operating expenses $ 27,888 $ 28,855 Variable lease cost Operating expenses 7,781 8,238 Short term lease cost Operating expenses 6,675 7,553 Finance Leases: Depreciation Operating expenses $ 221 $ 461 Interest expense Interest expense 33 37 Total $ 42,598 $ 45,144
Weighted Average Lease Term and Discount Rates	The following table presents the weighted average lease term and discount rates for leases as of March 31, 2021 and March 31, 2020: March 31, 2021 March 31, 2020 Operating Leases: Weighted average remaining lease term (years) 5.5 years 5.0 years Weighted average discount rate 5.16% 5.17% Finance Leases: Weighted average remaining lease term (years) 3.1 years 3.5 years Weighted average discount rate 4.81% 4.92%
Maturity of Operating Lease Liability	The following table presents future payments due under leases reconciled to lease liabilities as of March 31, 2021: Finance Leases Operating Leases Year ended March 31, 2022 $ 264 $ 24,663 2023 218 16,618 2024 159 10,717 2025 48 6,977 2026 26 5,114 Thereafter — 12,997 Total undiscounted lease payments 715 77,086 Present value discount 44 12,784 Lease liability $ 671 $ 64,302
Maturity of Finance Lease Liability	The following table presents future payments due under leases reconciled to lease liabilities as of March 31, 2021: Finance Leases Operating Leases Year ended March 31, 2022 $ 264 $ 24,663 2023 218 16,618 2024 159 10,717 2025 48 6,977 2026 26 5,114 Thereafter — 12,997 Total undiscounted lease payments 715 77,086 Present value discount 44 12,784 Lease liability $ 671 $ 64,302
Supplemental Cash Flow Information Related to Leases	The following table presents supplemental disclosures of cash flow information related to leases for the fiscal years ended March 31, 2021 and March 31, 2020: March 31, 2021 March 31, 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from finance leases $ 33 $ 37 Operating cash flows from operating leases 28,036 28,593 Financing cash flows from finance leases 216 461 Supplemental non-cash information on lease liabilities arising from right-of-use assets: Right-of-use assets obtained in exchange for new finance lease liabilities $ 266 $ — Right-of-use assets obtained in exchange for new operating lease liabilities 14,763 11,902

Acquisition (Tables)

Acquisition (Tables)	12 Months Ended
	Mar. 31, 2021
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The final amounts recognized in connection with the Alpha business combination are in the table below. 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 54,941 Other liabilities 12,642 Total liabilities assumed $ 145,304 Net assets acquired $ 423,274 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 423,274 Goodwill $ 319,228
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination	The following table summarizes the fair value of Alpha's identifiable intangible assets and their respective 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, 2018: Fiscal year ended March 31, 2019 Net sales $ 3,250,332 Net earnings attributable to EnerSys stockholders 181,915 Net earnings per share attributable to EnerSys stockholders - basic 4.19 Net earnings per share attributable to EnerSys stockholders - assuming dilution 4.12

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Mar. 31, 2021
Inventory Disclosure [Abstract]
Summary Of Net Inventories	March 31, 2021 2020 Raw materials $ 147,040 $ 141,906 Work-in-process 97,715 91,520 Finished goods 273,492 286,034 Total $ 518,247 $ 519,460

Property, Plant, and Equipment

Property, Plant, and Equipment (Tables)	12 Months Ended
	Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Summary Of Property, Plant, And Equipment	Property, plant, and equipment consist of: March 31, 2021 2020 Land, buildings, and improvements $ 313,031 $ 291,271 Machinery and equipment 822,725 722,955 Construction in progress 60,049 93,921 1,195,805 1,108,147 Less accumulated depreciation (698,749) (628,133) Total $ 497,056 $ 480,014

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Mar. 31, 2021
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, 2021 2020 Gross Accumulated Net Gross Accumulated Net Indefinite-lived intangible assets: Trademarks $ 148,164 $ (953) $ 147,211 $ 147,352 $ (953) $ 146,399 Finite-lived intangible assets: Customer relationships 298,576 (87,308) 211,268 292,155 (64,855) 227,300 Non-compete 2,825 (2,825) — 3,021 (2,817) 204 Technology 97,349 (29,561) 67,788 96,047 (20,349) 75,698 Trademarks 8,012 (3,381) 4,631 8,012 (1,928) 6,084 Licenses 1,196 (1,196) — 1,196 (1,196) — Total $ 556,122 $ (125,224) $ 430,898 $ 547,783 $ (92,098) $ 455,685
Schedule Of Changes In The Carrying Amount Of Goodwill By Business Segment	The following table presents the amount of goodwill that has been reassigned to each of the Company's reporting units as of April 1, 2020, using the relative fair value approach, as well as changes in the carrying amount of goodwill by segment during fiscal 2020 and 2021: Energy Systems Motive Power Specialty Americas (2) EMEA Asia (2) Total Balance at April 1, 2019 $ — $ — $ — $ 470,194 $ 143,269 $ 42,936 $ 656,399 Acquisitions during the year — — — 72,056 1,732 — 73,788 Measurement period adjustments — — — (1,390) — — (1,390) Goodwill impairment charge — — — — — (39,713) (39,713) Foreign currency translation adjustment — — — (16,704) (5,221) (3,223) (25,148) Balance at March 31, 2020 — — — 524,156 139,780 — 663,936 Reallocation to new Reporting Units (1) 263,150 308,497 92,289 (524,156) (139,780) — — Balance at April 1, 2020 263,150 308,497 92,289 — — — 663,936 Measurement period adjustments 1,348 — 1,648 — — — 2,996 Foreign currency translation adjustment 15,178 18,558 4,925 — — — 38,661 Balance at March 31, 2021 $ 279,676 $ 327,055 $ 98,862 $ — $ — $ — $ 705,593 (1) Represents the reallocation of goodwill as a result of the Company reorganizing its segments as described in Note 1. (2) Goodwill is net of accumulated impairment charges of $57,845 and $44,892 in the legacy Americas and Asia reporting units, respectively, as of March 31, 2020.

Prepaid and Other Current Ass_2

Prepaid and Other Current Assets (Tables)	12 Months Ended
	Mar. 31, 2021
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, 2021 2020 Contract assets $ 46,451 $ 39,048 Prepaid non-income taxes 25,251 23,069 Non-trade receivables 10,925 19,380 Prepaid income taxes 6,562 13,062 Other 28,492 26,034 Total $ 117,681 $ 120,593

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Mar. 31, 2021
Payables and Accruals [Abstract]
Summary Of Accrued Expenses	Accrued expenses consist of the following: March 31, 2021 2020 Payroll and benefits $ 92,305 $ 62,131 Accrued selling expenses 47,364 43,292 Hagen exit related accruals 24,593 — Operating lease liabilities 21,774 21,128 Warranty 18,982 27,766 Contract liabilities 15,992 17,342 VAT and other non-income taxes 14,267 14,209 Freight 13,097 14,222 Interest 10,592 11,180 Tax Act - Transition Tax 6,172 6,172 Income taxes payable 5,683 304 Restructuring 2,595 3,325 Pension 1,514 1,350 Other 43,793 49,319 Total $ 318,723 $ 271,740

Debt (Tables)

Debt (Tables)	12 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Schedule Of Long-Term Debt	The following summarizes the Company’s long-term debt as of March 31, 2021 and March 31, 2020: 2021 2020 Principal Unamortized Issuance Costs Principal Unamortized Issuance Costs Senior Notes $ 600,000 $ 5,106 $ 600,000 $ 6,306 Amended Credit Facility, due 2022 376,039 1,315 513,224 2,187 $ 976,039 $ 6,421 $ 1,113,224 $ 8,493 Less: Unamortized issuance costs 6,421 8,493 Long-term debt, net of unamortized issuance costs $ 969,618 $ 1,104,731

Other Liabilities (Tables)

Other Liabilities (Tables)	12 Months Ended
	Mar. 31, 2021
Other Liabilities Disclosure [Abstract]
Schedule Of Other Long-Term Liabilities	Other liabilities consist of the following: March 31, 2021 2020 Tax Act - Transition Tax $ 53,045 $ 58,630 Operating lease liabilities 42,528 51,215 Pension 40,450 40,496 Warranty 39,980 35,759 Liability for uncertain tax positions 7,185 8,080 Contract liabilities 2,072 8,356 Other 10,508 11,280 Total $ 195,768 $ 213,816

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
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, 2021 and March 31, 2020 and the basis for that measurement: Total Fair Value Measurement March 31, 2021 Quoted Price in Significant Significant Lead forward contracts $ (1,980) $ — $ (1,980) $ — Foreign currency forward contracts 424 — 424 — Total derivatives $ (1,556) $ — $ (1,556) $ — Total Fair Value Measurement March 31, 2020 Quoted Price in Significant Significant Lead forward contracts $ (2,433) $ — $ (2,433) $ — Foreign currency forward contracts 1 — 1 — Total derivatives $ (2,432) $ — $ (2,432) $ —
Carrying Amounts And Estimated Fair Values Of Company's Financial Instruments	The carrying amounts and estimated fair values of the Company’s derivatives and Senior Notes at March 31, 2021 and 2020 were as follows: March 31, 2021 March 31, 2020 Carrying Fair Value Carrying Fair Value Financial assets: Derivatives (1) $ — $ — $ — $ — Financial liabilities: Senior Notes (2) $ 600,000 $ 621,000 $ 600,000 $ 573,000 Derivatives (1) 1,556 1,556 2,432 2,432 (1) Represents lead and foreign currency forward contracts (see Note 13 for asset and liability positions of the lead and foreign currency forward contracts at March 31, 2021 and March 31, 2020).

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Mar. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value Of Derivative Instruments In The Consolidated Balance Sheets	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, 2021 and 2020 Derivatives and Hedging Activities Designated as Cash Flow Hedges Derivatives and Hedging Activities Not Designated as Hedging Instruments March 31, 2021 March 31, 2020 March 31, 2021 March 31, 2020 Prepaid and other current assets: Foreign currency forward contracts $ 524 $ — $ — $ 375 Total assets $ 524 $ — $ — $ 375 Accrued expenses: Lead forward contracts $ 1,980 $ 2,433 $ — $ — Foreign currency forward contracts — 374 100 — Total liabilities $ 1,980 $ 2,807 $ 100 $ —
The Effect of Derivative Instruments on the Consolidated Statements of Income	The Effect of Derivative Instruments on the Consolidated Statements of Income For the fiscal year ended March 31, 2021 Derivatives Designated as Cash Flow Hedges Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion) Location of Gain Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion) Lead forward contracts $ 202 Cost of goods sold $ (7,411) Foreign currency forward contracts 130 Cost of goods sold (492) Total $ 332 $ (7,903) The Effect of Derivative Instruments on the Consolidated Statements of Income For the fiscal year ended March 31, 2020 Derivatives Designated as Cash Flow Hedges Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion) Location of Gain Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion) Lead forward contracts $ (8,683) Cost of goods sold $ (1,690) Foreign currency forward contracts (54) Cost of goods sold 539 Total $ (8,737) $ (1,151) 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 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)
Effect Of Derivative Instruments	Derivatives Not Designated as Hedging Instruments Location of Gain (Loss) Pretax Gain (Loss) Foreign currency forward contracts Other (income) expense, net $ 430 Total $ 430 Derivatives Not Designated as Hedging Instruments Location of Gain (Loss) Pretax Gain (Loss) Foreign currency forward contracts Other (income) expense, net $ (178) Total $ (178) Derivatives Not Designated as Hedging Instruments Location of Gain (Loss) Pretax Gain (Loss) Foreign currency forward contracts Other (income) expense, net $ (1,856) Total $ (1,856)

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income Tax Expense	Fiscal year ended March 31, 2021 2020 2019 Current income tax expense Current: Federal $ 12,591 $ 9,185 $ 6,377 State 4,133 2,561 5,027 Foreign 19,031 14,561 16,636 Total current income tax expense 35,755 26,307 28,040 Deferred income tax (benefit) expense Federal 1,495 5,489 (5,031) State 735 741 (669) Foreign (11,224) (22,716) (756) Total deferred income tax (benefit) expense (8,994) (16,486) (6,456) Total income tax expense $ 26,761 $ 9,821 $ 21,584
Earnings Before Income Taxes	Earnings before income taxes consists of the following: Fiscal year ended March 31, 2021 2020 2019 United States $ 56,055 $ 36,193 $ 53,339 Foreign 114,080 110,744 128,872 Earnings before income taxes $ 170,135 $ 146,937 $ 182,211
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, 2021 2020 Deferred tax assets: Accounts receivable $ 2,029 $ 1,110 Inventories 8,831 5,010 Net operating loss carryforwards 62,663 44,340 Lease liabilities 15,685 18,168 Accrued expenses 36,775 26,113 Other assets 18,173 19,793 Gross deferred tax assets 144,156 114,534 Less valuation allowance (31,928) (20,951) Total deferred tax assets 112,228 93,583 Deferred tax liabilities: Property, plant and equipment 38,364 30,229 Lease Right-of-use assets 15,685 18,168 Intangible assets 66,743 66,529 Other liabilities 2,636 1,217 Total deferred tax liabilities 123,428 116,143 Net deferred tax liabilities $ (11,200) $ (22,560)
Schedule of Change in Valuation Allowance	The following table sets forth the changes in the Company's valuation allowance for fiscal 2021, 2020 and 2019: Balance at Additions Valuation Allowance Reversal Business Combination Adjustments Other (1) Balance at Fiscal year ended March 31, 2019 $ 15,255 $ 2,978 $ (99) $ 1,157 $ (1,772) $ 17,519 Fiscal year ended March 31, 2020 17,519 7,494 (3,145) (688) (229) 20,951 Fiscal year ended March 31, 2021 20,951 8,437 (2,904) 6,384 (940) 31,928 (1) Includes the impact of currency changes and the expiration of net operating losses for which a full valuation allowance was recorded.
Reconciliation Of Income Taxes At The Statutory Rate	A reconciliation of income taxes at the statutory rate (21.0% for fiscal 2021, 2020 and 2019) to the income tax provision is as follows: Fiscal year ended March 31, 2021 2020 2019 United States statutory income tax expense $ 35,729 $ 30,857 $ 38,264 Increase (decrease) resulting from: Impact of Tax Act — — (13,483) State income taxes, net of federal effect 4,000 2,764 3,285 Nondeductible expenses and other 5,273 5,953 4,378 Legal proceedings charge - European Competition Investigations — — 2,405 Net effect of GILTI, FDII, BEAT 1,985 3,025 2,320 Goodwill impairment - See Note 7 — 10,714 — Effect of foreign operations (20,035) (17,605) (16,763) Valuation allowance 5,533 4,349 2,879 Switzerland Tax Reform (1,883) (26,846) — Research and Development Credit (3,841) (3,390) (1,701) Income tax expense $ 26,761 $ 9,821 $ 21,584
Reconciliation Of Unrecognized Tax Benefits	The following table summarizes activity of the total amounts of unrecognized tax benefits: Fiscal year ended March 31, 2021 2020 2019 Balance at beginning of year $ 7,795 $ 20,165 $ 1,568 Increases related to current year tax positions 346 598 129 Increases related to the Alpha acquisition — 769 7,840 Increases related to prior year tax positions 325 — 11,463 Decreases related to prior tax positions — (11,463) (544) Decreases related to prior year tax positions settled — — (93) Lapse of statute of limitations (1,681) (2,274) (198) Balance at end of year $ 6,785 $ 7,795 $ 20,165

Retirement Plans (Tables)

Retirement Plans (Tables)	12 Months Ended
	Mar. 31, 2021
Retirement Benefits [Abstract]
Components Of Net Periodic Pension Cost	Net periodic pension cost for fiscal 2021, 2020 and 2019, includes the following components: United States Plans International Plans Fiscal year ended March 31, Fiscal year ended March 31, 2021 2020 2019 2021 2020 2019 Service cost $ — $ — $ — $ 993 $ 906 $ 997 Interest cost 533 616 631 1,388 1,485 1,831 Expected return on plan assets (272) (448) (514) (1,899) (2,136) (2,151) Amortization and deferral 476 188 184 1,053 910 1,520 Net periodic benefit cost $ 737 $ 356 $ 301 $ 1,535 $ 1,165 $ 2,197
Summary Of Change In Projected Benefit Obligation	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, 2021 2020 2021 2020 Change in projected benefit obligation Benefit obligation at the beginning of the period $ 18,111 $ 16,647 $ 68,602 $ 75,038 Service cost — — 993 906 Interest cost 533 616 1,388 1,485 Benefits paid, inclusive of plan expenses (802) (1,132) (2,087) (2,262) Plan curtailments and settlements — — (91) (678) Actuarial losses (gains) (36) 1,980 7,761 (3,024) Foreign currency translation adjustment — — 6,686 (2,863) Benefit obligation at the end of the period $ 17,806 $ 18,111 $ 83,252 $ 68,602
Summary Of Change In Plan Assets	Change in plan assets Fair value of plan assets at the beginning of the period $ 12,036 $ 13,763 $ 32,831 $ 36,791 Actual return on plan assets 4,379 (649) 6,272 (1,605) Employer contributions 652 54 1,869 2,098 Benefits paid, inclusive of plan expenses (802) (1,132) (2,087) (2,262) Plan curtailments and settlements — — (91) (482) Foreign currency translation adjustment — — 4,050 (1,709) Fair value of plan assets at the end of the period $ 16,265 $ 12,036 $ 42,844 $ 32,831 Funded status deficit $ (1,541) $ (6,075) $ (40,408) $ (35,771)
Summary Of Amounts Recognized In The Balance Sheets	March 31, 2021 2020 Amounts recognized in the Consolidated Balance Sheets consist of: Non current assets $ 15 $ — Accrued expenses (1,514) (1,350) Other liabilities (40,450) (40,496) Funded status deficit $ (41,949) $ (41,846)
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, 2021, 2020 and 2019: Fiscal year ended March 31, 2021 2020 2019 Amounts recorded in AOCI before taxes: Prior service cost $ (230) $ (258) $ (307) Net loss (25,450) (25,796) (24,051) Net amount recognized $ (25,680) $ (26,054) $ (24,358)
Summary Of Changes In AOCI	Fiscal year ended March 31, 2021 2020 2019 Changes in plan assets and benefit obligations: New prior service cost $ — $ — $ — Net loss (gain) arising during the year (753) 3,793 (99) Effect of exchange rates on amounts included in AOCI 1,909 (804) (1,984) Amounts recognized as a component of net periodic benefit costs: Amortization of prior service cost (46) (43) (45) Amortization or settlement recognition of net loss (1,484) (1,250) (1,659) Total recognized in other comprehensive (income) loss $ (374) $ 1,696 $ (3,787)
Summary Of Recognized Components Of Net Periodic Pension Cost Included In Accumulated Other Comprehensive Income	The amounts included in AOCI as of March 31, 2021 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 $ (46) Net loss (1,163) Net amount expected to be recognized $ (1,209)
Summary Of Accumulated Benefit Obligation Related To All Defined Pension Plans	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 fiscal year are as follows: United States Plans International Plans March 31, March 31, 2021 2020 2021 2020 All defined benefit plans: Accumulated benefit obligation $ 17,806 $ 18,111 $ 78,360 $ 65,336 Unfunded defined benefit plans: Projected benefit obligation $ — $ — $ 34,932 $ 30,773 Accumulated benefit obligation — — 31,970 28,926 Defined benefit plans with a projected benefit obligation in excess of the fair value of plan assets: Projected benefit obligation $ 17,806 $ 18,111 $ 82,814 $ 68,602 Fair value of plan assets 16,265 12,036 42,390 32,831 Defined benefit plans with an accumulated benefit obligation in excess of the fair value of plan assets: Projected benefit obligation $ 17,806 $ 18,111 $ 82,814 $ 68,602 Accumulated benefit obligation 17,806 18,111 77,928 65,336 Fair value of plan assets 16,265 12,036 42,390 32,831
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, 2021 2020 2019 2021 2020 2019 Discount rate 3.0 % 3.8 % 3.9 % 1.3%-2.3% 1.0%-2.7% 1.4%-3.3% Expected return on plan assets 6.0 6.3 6.3 3.8-5.5 4.3-6.0 4.1-6.0 Rate of compensation increase N/A N/A N/A 2.0-3.5 2.0-4.0 1.8-4.0 N/A = not applicable
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, 2021 2020 2021 2020 Discount rate 3.0 % 3.0 % 0.5%-2.3% 1.3%-2.3% Rate of compensation increase N/A N/A 1.5-4.0 2.0-3.5 N/A = not applicable
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, 2021 and 2020 and the basis for that measurement: March 31, 2021 United States Plans International Plans Total Fair Quoted Price Significant Significant Total Fair Quoted Price Significant Significant Asset category: Cash and cash equivalents $ 1,454 $ 1,454 $ — $ — $ 81 $ 81 $ — $ — Equity securities US (a) 10,435 10,435 — — — — — — International (b) — — — — 28,144 — 28,144 — Fixed income (c) 4,376 4,376 — — 14,619 — 14,619 — Total $ 16,265 $ 16,265 $ — $ — $ 42,844 $ 81 $ 42,763 $ — March 31, 2020 United States Plans International Plans Total Fair Quoted Price Significant Significant Total Quoted Price Significant Significant Asset category: Cash and cash equivalents $ 1,221 $ 1,221 $ — $ — $ 141 $ 141 $ — $ — Equity securities US (a) 6,860 6,860 — — — — — — International (b) — — — — 20,059 — 20,059 — Fixed income (c) 3,955 3,955 — — 12,631 — 12,631 — Total $ 12,036 $ 12,036 $ — $ — $ 32,831 $ 141 $ 32,690 $ — 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: 2022 $ 3,181 2023 3,253 2024 3,172 2025 3,794 2026 4,073 Years 2027-2031 22,308

Stockholders_ Equity (Tables)

Stockholders’ Equity (Tables)	12 Months Ended
	Mar. 31, 2021
Stockholders' Equity and Noncontrolling Interests [Abstract]
Change in Number of Shares of Common Stock Outstanding	The following demonstrates the change in the number of shares of common stock outstanding during fiscal years ended March 31, 2019, 2020 and 2021, respectively: 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 towards 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 Purchase of treasury stock (581,140) Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes 283,695 Shares outstanding as of March 31, 2020 42,323,305 Purchase of treasury stock — Shares issued under equity-based compensation plans, net of equity awards surrendered for option price and taxes 429,715 Shares outstanding as of March 31, 2021 42,753,020
Components Of Accumulated Other Comprehensive Income	The components of AOCI, net of tax, are as follows: Beginning Before Reclassifications Amount Reclassified from AOCI Ending March 31, 2021 Pension funded status adjustment $ (22,794) $ 680 $ 1,167 $ (20,947) Net unrealized gain (loss) on derivative instruments (5,923) 250 6,033 360 Foreign currency translation adjustment (186,289) 90,993 — (95,296) Accumulated other comprehensive loss $ (215,006) $ 91,923 $ 7,200 $ (115,883) March 31, 2020 Pension funded status adjustment $ (20,791) $ (2,819) $ 816 $ (22,794) Net unrealized gain (loss) on derivative instruments (130) (6,672) 879 (5,923) Foreign currency translation adjustment (121,761) (64,528) — (186,289) Accumulated other comprehensive loss $ (142,682) $ (74,019) $ 1,695 $ (215,006) 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)
Reclassification out of Accumulated Other Comprehensive Income	The following table presents reclassifications from AOCI during the twelve months ended March 31, 2021: 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 $ 7,903 Cost of goods sold Tax benefit (1,870) Net unrealized loss on derivative instruments, net of tax $ 6,033 Defined benefit pension costs: Prior service costs and deferrals $ 1,529 Net periodic benefit cost, included in other (income) expense, net - See Note 15 Tax benefit (362) Net periodic benefit cost, net of tax $ 1,167 The following table presents reclassifications from AOCI during the twelve months ended March 31, 2020: 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 $ 1,151 Cost of goods sold Tax benefit (272) Net unrealized loss on derivative instruments, net of tax $ 879 Defined benefit pension costs: Prior service costs and deferrals $ 1,098 Net periodic benefit cost, included in other (income) expense, net - See Note 15 Tax benefit (282) Net periodic benefit cost, net of tax $ 816 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 15 Tax benefit (331) Net periodic benefit cost, net of tax $ 1,373

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Summary Of Stock Option Activity	For purposes of determining the fair value of stock options granted, the Company used a Black-Scholes Model with the following assumptions: 2021 2020 2019 Risk-free interest rate 0.39 % 1.52 % 2.77 % Dividend yield 0.93 % 1.21 % 0.93 % Expected life (years) 6 6 6 Volatility 37.2 % 29.1 % 26.8 % The following table summarizes the Company’s stock option activity in the years indicated: Number of Weighted- Weighted- Aggregate 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 — Expired — — — Options outstanding as of March 31, 2019 554,906 8.0 $ 72.31 $ 1,040 Granted 284,109 57.75 — Exercised (24,826) 57.60 383 Forfeited (22,607) 72.19 88 Expired — — — Options outstanding as of March 31, 2020 791,582 7.8 $ 67.55 $ — Granted 295,068 79.62 — Exercised (247,975) 66.11 6,382 Forfeited (34,854) 69.20 290 Expired (4,320) 80.25 — Options outstanding as of March 31, 2021 799,501 7.8 $ 72.31 $ 14,781 Options exercisable as of March 31, 2021 291,440 6.1 $ 73.25 $ 5,114 Options vested and expected to vest, as of March 31, 2021 782,935 7.8 $ 72.28 $ 14,497 For purposes of determining the fair value of TSRs granted in fiscal 2020 and fiscal 2019, the Company used a Monte Carlo Simulation with the following assumptions: 2020 2019 Risk-free interest rate 1.50 % 2.66 % Dividend yield — % — % Expected life (years) 3 3 Volatility 34.39 % 26.41 %
Summary Of Information Regarding Stock Options Outstanding And Exercisable	The following table summarizes information regarding stock options outstanding as of March 31, 2021: Range of Exercise Prices Number of Weighted- Weighted- $57.60-$60.00 231,025 7.9 $ 57.73 $60.01-$70.00 56,530 3.9 $ 68.78 $70.01-$83.14 511,946 8.2 $ 79.28 799,501 7.8 $ 72.31
Summary Of The Changes In Restricted Stock Units And Market Share Units	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 2021 is presented below: Restricted Stock Units (RSU) Market condition-based Share Units (TSR) Performance condition-based Share Units (PSU) Number of Weighted- Number of Weighted- Number of Weighted- Non-vested awards as of March 31, 2020 880,335 $ 55.61 208,720 $ 80.78 101,130 $ 57.49 Granted 324,262 71.53 37 79.51 — — Stock dividend 8,125 57.69 1,165 83.15 917 57.52 Performance factor — — — — — — Vested (279,995) 58.01 (65,096) 71.17 — — Forfeitures (52,443) 68.94 (18,866) 98.88 (3,701) 56.04 Non-vested awards as of March 31, 2021 880,284 $ 60.07 125,960 $ 83.48 98,346 $ 57.55

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Reconciliation From Basic To Diluted Average Common Shares And Net Earnings Per Common Share	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, 2021 2020 2019 Net earnings attributable to EnerSys stockholders $ 143,374 $ 137,116 $ 160,239 Weighted-average number of common shares outstanding: Basic 42,548,449 42,411,834 42,335,023 Dilutive effect of: Common shares from exercise and lapse of equity awards, net of shares assumed reacquired 675,954 484,941 673,929 Diluted weighted-average number of common shares outstanding 43,224,403 42,896,775 43,008,952 Basic earnings per common share attributable to EnerSys stockholders $ 3.37 $ 3.23 $ 3.79 Diluted earnings per common share attributable to EnerSys stockholders $ 3.32 $ 3.20 $ 3.73 Anti-dilutive equity awards not included in diluted weighted-average common shares 281,483 698,546 355,728

Restructuring, Exit and Other C

Restructuring, Exit and Other Charges (Tables)	12 Months Ended
	Mar. 31, 2021
Restructuring and Related Activities [Abstract]
Acquisition And Non-Acquisition Related Restructuring Reserve	Restructuring and exit charges for fiscal 2021, 2020 and 2019 by reportable segments are as follows: Fiscal year ended March 31, 2021 Energy Systems Motive Power Specialty Total Restructuring charges $ 3,187 $ 4,012 $ 169 $ 7,368 Exit charges — 32,786 220 33,006 Restructuring and other exit charges $ 3,187 $ 36,798 $ 389 $ 40,374 Fiscal year ended March 31, 2020 Energy Systems Motive Power Specialty Total Restructuring charges $ 6,808 $ 1,860 $ 2,318 $ 10,986 Exit charges 526 5,541 3,713 9,780 Restructuring and other exit charges $ 7,334 $ 7,401 $ 6,031 $ 20,766 Fiscal year ended March 31, 2019 Energy Systems Motive Power Specialty Total Restructuring charges $ 5,115 $ 4,795 $ 713 $ 10,623 Exit charges 5,477 957 17,652 24,086 Restructuring and other exit charges $ 10,592 $ 5,752 $ 18,365 $ 34,709 A roll-forward of the restructuring reserve is as follows: Employee Other Total 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 Accrued 10,395 402 10,797 Costs incurred (9,179) (995) (10,174) Foreign currency impact and other (247) (3) (250) Balance at March 31, 2020 $ 3,325 $ — $ 3,325 Accrued 6,537 831 7,368 Costs incurred (7,550) (831) (8,381) Foreign currency impact and other 283 — 283 Balance at March 31, 2021 $ 2,595 $ — $ 2,595

Warranty (Tables)

Warranty (Tables)	12 Months Ended
	Mar. 31, 2021
Guarantees [Abstract]
Analysis Of Changes In Liability For Product Warranties	An analysis of changes in the liability for product warranties is as follows: Fiscal year ended March 31, 2021 2020 2019 Balance at beginning of year $ 63,525 $ 54,568 $ 50,602 Current year provisions 27,645 27,622 23,679 Costs incurred (34,346) (25,778) (25,053) Warranty reserves of acquired businesses — 6,995 7,535 Foreign currency translation adjustment 2,138 118 (2,195) Balance at end of year $ 58,962 $ 63,525 $ 54,568

Other (Income) Expense, Net (Ta

Other (Income) Expense, Net (Tables)	12 Months Ended
	Mar. 31, 2021
Other Income and Expenses [Abstract]
Summary Of Other (Income) Expense, Net	Other (income) expense, net consists of the following: Fiscal year ended March 31, 2021 2020 2019 Foreign exchange transaction losses (gains) $ 6,696 $ 264 $ (3,044) Non-service components of pension expense 1,279 615 1,502 Other (171) (1,294) 928 Total $ 7,804 $ (415) $ (614)

Business Segments (Tables)

Business Segments (Tables)	12 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Summary Of Financial Information Related To The Company's Business Segments	Summarized financial information related to the Company’s reportable segments at March 31, 2021, 2020 and 2019 and for each of the fiscal years then ended is shown below. Fiscal year ended March 31, 2021 2020 2019 Net sales by segment to unaffiliated customers Energy Systems $ 1,380,278 $ 1,357,475 $ 1,086,279 Motive Power 1,163,710 1,348,193 1,391,844 Specialty 433,944 382,200 329,894 Total net sales $ 2,977,932 $ 3,087,868 $ 2,808,017 Operating earnings by segment Energy Systems $ 67,060 $ 67,809 $ 45,164 Motive Power 143,541 146,814 172,749 Specialty 46,148 42,454 44,077 Inventory step up to fair value relating to acquisitions - Energy Systems — (304) (7,789) Inventory step up to fair value relating to acquisitions - Specialty — (1,550) (2,590) Restructuring and other exit charges - Energy Systems (3,187) (7,284) (10,593) Restructuring and other exit charges - Motive Power (36,798) (2,021) (5,751) Restructuring and other exit charges - Specialty (389) (6,020) (18,365) Impairment of goodwill (3) — (39,713) — Impairment of indefinite-lived intangibles (3) — (4,549) — Fixed asset write-off relating to exit activities and other - Energy Systems — (50) — Fixed asset write-off relating to exit activities and other - Motive Power — (5,380) — Fixed asset write-off relating to exit activities - Specialty — (11) — Legal proceedings charge, net - Energy Systems — — (4,363) Legal proceedings charge, net - Motive Power — — (74) Total operating earnings (2) $ 216,375 $ 190,195 $ 212,465 Capital Expenditures Energy Systems $ 34,826 $ 40,768 $ 24,333 Motive Power 14,154 22,285 26,112 Specialty 21,040 38,372 19,927 Total $ 70,020 $ 101,425 $ 70,372 Depreciation and Amortization Energy Systems $ 57,864 $ 53,793 $ 32,052 Motive Power 21,706 20,900 20,725 Specialty 14,512 12,651 10,571 Total $ 94,082 $ 87,344 $ 63,348 (1) Reportable segments do not record inter-segment revenues and accordingly there are none to report. (2) The Company does not allocate interest expense or other (income) expense, net, to the reportable segments. (3) The impairment of goodwill and indefinite-lived intangibles in fiscal 2020 related to the Company's legacy reportable segments as discussed in Note 7. The Company's property, plant and equipment by reportable segments as of March 31, 2021 and 2020 are as follows: Property, plant and equipment, net March 31, 2021 March 31, 2020 Energy Systems $ 224,513 $ 182,122 Motive Power 152,468 153,438 Specialty 120,075 144,454 Total $ 497,056 $ 480,014

Quarterly Financial Data (Table

Quarterly Financial Data (Tables)	12 Months Ended
	Mar. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Summary Of Interim Financial Information	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 2021 ended on July 5, 2020, October 4, 2020, January 3, 2021, and March 31, 2021, respectively. The four quarters in fiscal 2020 ended on June 30, 2019, September 29, 2019, December 29, 2019, and March 31, 2020, respectively. 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Fiscal Year Fiscal year ended March 31, 2021 Net sales $ 704,924 $ 708,402 $ 751,067 $ 813,539 $ 2,977,932 Gross profit (1) 174,977 177,560 189,312 197,301 739,150 Operating earnings (2)(3) 53,220 55,415 56,071 51,669 216,375 Net earnings (4) 35,183 35,731 38,624 33,836 143,374 Net earnings attributable to EnerSys stockholders 35,183 35,731 38,624 33,836 143,374 Net earnings per common share attributable to EnerSys stockholders—basic $ 0.83 $ 0.84 $ 0.91 $ 0.79 $ 3.37 Net earnings per common share attributable to EnerSys stockholders—diluted $ 0.82 $ 0.83 $ 0.89 $ 0.78 $ 3.32 Fiscal year ended March 31, 2020 Net sales $ 780,230 $ 762,137 $ 763,698 $ 781,803 $ 3,087,868 Gross profit (5)(6) 201,512 197,317 185,241 200,796 784,866 Operating earnings (7)(8) 68,336 58,710 43,084 20,065 190,195 Net earnings (loss) (9) 48,636 62,698 27,305 (1,523) 137,116 Net earnings (loss) attributable to EnerSys stockholders 48,636 62,698 27,305 (1,523) 137,116 Net earnings (loss) per common share attributable to EnerSys stockholders—basic $ 1.14 $ 1.48 $ 0.65 $ (0.04) $ 3.23 Net earnings (loss) per common share attributable to EnerSys stockholders—diluted $ 1.13 $ 1.47 $ 0.64 $ (0.04) $ 3.20 (1) Included in Gross profit were receipts for business interruption relating to the Richmond, Kentucky motive power production facility, of $3,700, $1,456 and $2,344 for the first, second, and third quarters of fiscal 2021, respectively. (2) Also included in Operating earnings was a net gain of $4,397, recorded in the third quarter of fiscal 2021, relating to the final settlement of insurance recoveries and finalization of costs related to the replacement of property, plant and equipment of the aforementioned claim. (3) Included in Operating earnings were restructuring and other exit charges of $1,387, $3,119, $15,196 and $20,672 for the first, second, third and fourth quarters of fiscal 2021, respectively. (4) Included in net earnings was a tax benefit of $1,883 for the first quarter of fiscal 2021, on account of the Swiss tax reform. (5) Included in Gross profit were inventory adjustment relating to the inventory step up to fair value relating to the NorthStar acquisition of $3,845 and $(1,991) in the third and fourth quarter of fiscal 2020, respectively. (6) Included in Gross profit were receipts for business interruption relating to the Richmond, Kentucky motive power production facility, of $5,000 in the fourth quarter of fiscal 2020. (7) Included in Operating earnings were restructuring and other exit charges of $2,372, $6,282, $9,417 and $2,695 for the first, second, third and fourth quarters of fiscal 2020, respectively. (8) Included in Operating earnings for the fourth quarter of fiscal 2020 were charges relating to the impairment of goodwill for $39,713 and other indefinite-lived intangibles for $4,549.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - segment	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents include all highly liquid investments with an original maturity, when purchased, in months		three months
Number of operating segments	3
Number of reportable segments	3
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
Minimum
Summary Of Significant Accounting Policies [Line Items]
Percentage of investment ownership, consolidated	50.00%
Percentage of investment ownership, equity method	20.00%
Estimated useful lives of finite-lived assets		3 years
Minimum | Energy Systems Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period		one
Minimum | Motive Power Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period		one
Minimum | Specialty Transportation Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period		one
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%
Percentage of investment ownership, cost method	20.00%
Estimated useful lives of finite-lived assets		20 years
Maximum | Energy Systems Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period		twenty years
Maximum | Motive Power Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period		seven years
Maximum | Specialty Transportation Batteries
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period		four 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

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Schedule of Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Period	$ 15,246	$ 10,813	$ 12,643
Provision for doubtful accounts	178	4,821	1,385
Write-offs, net of Recoveries and Other	(2,432)	(388)	(3,215)
Balance at End of Period	$ 12,992	$ 15,246	$ 10,813

Revenue Recognition - Additiona

Revenue Recognition - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2021	Jan. 03, 2021	Oct. 04, 2020	Jul. 05, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Net sales	$ 813,539	$ 751,067	$ 708,402	$ 704,924	$ 781,803	$ 763,698	$ 762,137	$ 780,230	$ 2,977,932	$ 3,087,868	$ 2,808,017
Contract with customer, liability, current portion	15,992				17,342				15,992	17,342
Contract with customer, liability, noncurrent portion	2,072				8,356				2,072	8,356
Revenue recognized									14,064	18,697
Unbilled contracts receivable	46,451				$ 39,048				46,451	39,048
Right to recover product	4,271								4,271
Refund liability	$ 7,475								7,475
Transferred over Time
Disaggregation of Revenue [Line Items]
Net sales									155,217	142,153	100,809
Service
Disaggregation of Revenue [Line Items]
Net sales									$ 296,213	$ 270,704	$ 157,236

Revenue Recognition - Remaining

Revenue Recognition - Remaining Performance Obligation (Details) $ in Thousands	Mar. 31, 2021USD ($)
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 115,775
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-04-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 93,941
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-04-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 21,011
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, timing of satisfaction	2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-04-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 774
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, timing of satisfaction	3 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 49
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, timing of satisfaction	4 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-04-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, timing of satisfaction	5 years

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2021
Lessee, Lease, Description [Line Items]
Rental expense	$ 40,261
Minimum
Lessee, Lease, Description [Line Items]
Contract term		1 year
Maximum
Lessee, Lease, Description [Line Items]
Contract term		17 years

Leases - Balance Sheet Classifi

Leases - Balance Sheet Classification (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Leases [Abstract]
Operating lease right-of-use asset	$ 62,159	$ 70,045
Operating lease liabilities	21,774	21,128
Operating lease non-current liabilities	42,528	51,215
Finance lease right-of-use asset	573	540
Current portion of finance leases	236	162
Finance leases	$ 435	$ 407
Operating lease, right-of-use asset, statement of financial position	Other assets	Other assets
Operating lease, liability, current, statement of financial position	Accrued expenses	Accrued expenses
Operating lease, liability, noncurrent, statement of financial position	Other liabilities	Other liabilities
Finance lease, right-of-use asset, statement of financial position	Property, plant, and equipment, net	Property, plant, and equipment, net

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating Leases:
Operating lease cost	$ 27,888	$ 28,855
Variable lease cost	7,781	8,238
Short term lease cost	6,675	7,553
Finance Leases:
Depreciation	221	461
Interest expense	33	37
Total	$ 42,598	$ 45,144

Leases - Additional Informati_2

Leases - Additional Information Related to Leases (Details)	Mar. 31, 2021	Mar. 31, 2020
Operating Leases:
Weighted average remaining lease term (years)	5 years 6 months	5 years
Weighted average discount rate	5.16%	5.17%
Finance Leases:
Weighted average remaining lease term (years)	3 years 1 month 6 days	3 years 6 months
Weighted average discount rate	4.81%	4.92%

Leases - Finance and Operating

Leases - Finance and Operating Lease Maturity Schedules (Details) $ in Thousands	Mar. 31, 2021USD ($)
Finance Leases
2022	$ 264
2023	218
2024	159
2025	48
2026	26
Thereafter	0
Total undiscounted lease payments	715
Present value discount	44
Finance lease liability	671
Operating Leases
2022	24,663
2023	16,618
2024	10,717
2025	6,977
2026	5,114
Thereafter	12,997
Total undiscounted lease payments	77,086
Present value discount	12,784
Operating lease liabilities	$ 64,302

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from finance leases	$ 33	$ 37
Operating cash flows from operating leases	28,036	28,593
Financing cash flows from finance leases	216	461
Supplemental non-cash information on lease liabilities arising from right-of-use assets:
Right-of-use assets obtained in exchange for new finance lease liabilities	266	0
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 14,763	$ 11,902

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2019	Dec. 07, 2018	Mar. 31, 2021	Jan. 03, 2021	Oct. 04, 2020	Jul. 05, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Business Acquisition [Line Items]
Goodwill			$ 705,593				$ 663,936					$ 705,593	$ 663,936	$ 656,399
Estimated tax-deductible goodwill			110,063				120,708					110,063	120,708
Measurement period adjustments												2,996	(1,390)
Net sales			813,539	$ 751,067	$ 708,402	$ 704,924	781,803	$ 763,698	$ 762,137	$ 780,230		2,977,932	3,087,868	2,808,017
Net loss			(33,836)	$ (38,624)	(35,731)	$ (35,183)	$ 1,523	$ (27,305)	$ (62,698)	$ (48,636)		(143,374)	(137,116)	$ (160,627)
NorthStar
Business Acquisition [Line Items]
Payments to acquire businesses	$ 77,777
Debt assumed					107,018
Goodwill					76,784
NorthStar | Developed Technology Rights
Business Acquisition [Line Items]
Acquired intangible assets	$ 19,000
Estimated useful lives of finite-lived assets	10 years
NorthStar | Trademarks
Business Acquisition [Line Items]
Acquired intangible assets	$ 6,000
Estimated useful lives of finite-lived assets	5 years
Estimated tax-deductible goodwill					$ 68,522
NorthStar | Customer relationships
Business Acquisition [Line Items]
Acquired intangible assets	$ 9,000
Alpha
Business Acquisition [Line Items]
Payments to acquire businesses		$ 650,000
Debt assumed		145,304
Goodwill		319,228
Estimated tax-deductible goodwill			28,525									28,525
Initial purchase consideration		$ 750,000
Shares issued in acquisition (USD per share)		$ 84.92
Fair value of shares issued for net assets acquired		$ 93,268
Closing day spot rate (USD per share)		$ 79.20
Working capital adjustment		$ 766
Total purchase consideration		742,502
Net sales													162,454
Net loss													$ 1,252
Acquisition cost expensed												12,883
Inventory adjustment												$ 7,263
Alpha | Customer relationships
Business Acquisition [Line Items]
Acquired intangible assets		$ 221,000
N Holding AB
Business Acquisition [Line Items]
Measurement period adjustments			$ 2,996
Minimum
Business Acquisition [Line Items]
Estimated useful lives of finite-lived assets													3 years
Minimum | NorthStar | Customer relationships
Business Acquisition [Line Items]
Estimated useful lives of finite-lived assets	15 years
Maximum
Business Acquisition [Line Items]
Estimated useful lives of finite-lived assets													20 years
Total purchase consideration											$ 250,000
Maximum | NorthStar | Customer relationships
Business Acquisition [Line Items]
Estimated useful lives of finite-lived assets	18 years
Common Stock | Alpha
Business Acquisition [Line Items]
Shares issued in acquisition (in shares)		1,177,630

Acquisitions - Assets and Liabi

Acquisitions - Assets and Liabilities Acquired (Details) - USD ($) $ in Thousands	Dec. 07, 2018	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Business Acquisition [Line Items]
Goodwill		$ 705,593	$ 663,936	$ 656,399
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	54,941
Other liabilities	12,642
Total liabilities assumed	145,304
Net assets acquired	423,274
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
Goodwill	$ 319,228

Acquisitions - Summary of Intan

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

Acquisitions - Pro Forma Inform

Acquisitions - Pro Forma Information (Details) - Alpha $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2021USD ($)$ / shares
Business Acquisition [Line Items]
Net sales | $	$ 3,250,332
Net earnings attributable to EnerSys stockholders | $	$ 181,915
Net earnings per share attributable to EnerSys stockholders - basic (in dollars per share) | $ / shares	$ 4.19
Net earnings per share attributable to EnerSys stockholders - assuming dilution (in dollars per share) | $ / shares	$ 4.12

Inventories - Summary of Invent

Inventories - Summary of Inventories (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Inventory Disclosure [Abstract]
Raw materials	$ 147,040	$ 141,906
Work-in-process	97,715	91,520
Finished goods	273,492	286,034
Total	$ 518,247	$ 519,460

Property, Plant, and Equipmen_2

Property, Plant, and Equipment - Summary of Property, Plant, and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment, including finance lease right-of-use asset, gross	$ 1,195,805	$ 1,108,147
Less accumulated depreciation	(698,749)	(628,133)
Property, plant, and equipment, net	497,056	480,014
Land, buildings, and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, including finance lease right-of-use asset, gross	313,031	291,271
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, including finance lease right-of-use asset, gross	822,725	722,955
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, including finance lease right-of-use asset, gross	$ 60,049	$ 93,921

Property, Plant, and Equipmen_3

Property, Plant, and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 60,956	$ 56,331	$ 48,618
Interest capitalized	$ 1,319	$ 2,030	$ 1,581

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Schedule of Company's Other Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Intangible Assets [Line Items]
Gross Amount, Total	$ 556,122	$ 547,783
Accumulated Amortization ,Total	(125,224)	(92,098)
Net Amount ,Total	430,898	455,685
Trademarks
Intangible Assets [Line Items]
Indefinite-lived intangible assets, Gross Amount	148,164	147,352
Finite-lived intangible assets, Gross Amount	8,012	8,012
Indefinite-lived intangible assets, Accumulated Amortization	(953)	(953)
Finite-lived intangible assets, Accumulated Amortization	(3,381)	(1,928)
Indefinite-lived intangible assets, Net Amount	147,211	146,399
Finite-lived intangible assets, Net Amount	4,631	6,084
Customer relationships
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	298,576	292,155
Finite-lived intangible assets, Accumulated Amortization	(87,308)	(64,855)
Finite-lived intangible assets, Net Amount	211,268	227,300
Noncompete Agreements
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	2,825	3,021
Finite-lived intangible assets, Accumulated Amortization	(2,825)	(2,817)
Finite-lived intangible assets, Net Amount	0	204
Patents
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	97,349	96,047
Finite-lived intangible assets, Accumulated Amortization	(29,561)	(20,349)
Finite-lived intangible assets, Net Amount	67,788	75,698
Licenses
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	1,196	1,196
Finite-lived intangible assets, Accumulated Amortization	(1,196)	(1,196)
Finite-lived intangible assets, Net Amount	$ 0	$ 0

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Indefinite-lived Intangible Assets [Line Items]
Amortization expense, related to finite-lived intangible assets			$ 33,126	$ 31,013	$ 14,730
Expected amortization expense, 2018	$ 32,624		32,624
Expected amortization expense, 2019	30,399		30,399
Expected amortization expense, 2020	27,545		27,545
Expected amortization expense, 2021	26,552		26,552
Expected amortization expense, 2022	25,618		25,618
Impairment of goodwill	39,713		0	39,713	$ 0
Impairment of indefinite-lived intangible assets	4,549
Estimated tax-deductible goodwill	$ 110,063	$ 120,708	$ 110,063	120,708
Asia
Indefinite-lived Intangible Assets [Line Items]
Impairment of goodwill		39,713
Asia
Indefinite-lived Intangible Assets [Line Items]
Impairment of goodwill				$ 39,713
Trademarks | EMEA
Indefinite-lived Intangible Assets [Line Items]
Impairment of indefinite-lived intangible assets		$ 4,549

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill by Business Segment (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Goodwill [Roll Forward]
Balance at beginning of year		$ 663,936	$ 656,399
Acquisitions during the year			73,788
Measurement period adjustments		2,996	(1,390)
Goodwill impairment charge	$ (39,713)	0	(39,713)	$ 0
Foreign currency translation adjustment		38,661	(25,148)
Balance at end of year	705,593	705,593	663,936	656,399
Goodwill Reallocation, Adjusted Balance
Goodwill [Roll Forward]
Balance at beginning of year		663,936
Balance at end of year			663,936
Energy Systems
Goodwill [Roll Forward]
Measurement period adjustments		1,348
Foreign currency translation adjustment		15,178
Balance at end of year	279,676	279,676
Energy Systems | Reallocation to new Reporting Units
Goodwill [Roll Forward]
Balance at beginning of year		263,150
Balance at end of year			263,150
Energy Systems | Goodwill Reallocation, Adjusted Balance
Goodwill [Roll Forward]
Balance at beginning of year		263,150
Balance at end of year			263,150
Motive Power
Goodwill [Roll Forward]
Measurement period adjustments		0
Foreign currency translation adjustment		18,558
Balance at end of year	327,055	327,055
Motive Power | Reallocation to new Reporting Units
Goodwill [Roll Forward]
Balance at beginning of year		308,497
Balance at end of year			308,497
Motive Power | Goodwill Reallocation, Adjusted Balance
Goodwill [Roll Forward]
Balance at beginning of year		308,497
Balance at end of year			308,497
Specialty
Goodwill [Roll Forward]
Measurement period adjustments		1,648
Foreign currency translation adjustment		4,925
Balance at end of year	98,862	98,862
Specialty | Reallocation to new Reporting Units
Goodwill [Roll Forward]
Balance at beginning of year		92,289
Balance at end of year			92,289
Specialty | Goodwill Reallocation, Adjusted Balance
Goodwill [Roll Forward]
Balance at beginning of year		92,289
Balance at end of year			92,289
Americas
Goodwill [Roll Forward]
Balance at beginning of year		524,156	470,194
Acquisitions during the year			72,056
Measurement period adjustments			(1,390)
Foreign currency translation adjustment			(16,704)
Balance at end of year	0	0	524,156	470,194
Accumulated impairment charges			57,845
Americas | Reallocation to new Reporting Units
Goodwill [Roll Forward]
Balance at beginning of year		(524,156)
Balance at end of year			(524,156)
Americas | Goodwill Reallocation, Adjusted Balance
Goodwill [Roll Forward]
Balance at beginning of year		0
Balance at end of year			0
EMEA
Goodwill [Roll Forward]
Balance at beginning of year		139,780	143,269
Acquisitions during the year			1,732
Foreign currency translation adjustment			(5,221)
Balance at end of year	0	0	139,780	143,269
EMEA | Reallocation to new Reporting Units
Goodwill [Roll Forward]
Balance at beginning of year		(139,780)
Balance at end of year			(139,780)
EMEA | Goodwill Reallocation, Adjusted Balance
Goodwill [Roll Forward]
Balance at beginning of year		0
Balance at end of year			0
Asia
Goodwill [Roll Forward]
Balance at beginning of year		0	42,936
Goodwill impairment charge			(39,713)
Foreign currency translation adjustment			(3,223)
Balance at end of year	$ 0	0	0	$ 42,936
Accumulated impairment charges			44,892
Asia | Goodwill Reallocation, Adjusted Balance
Goodwill [Roll Forward]
Balance at beginning of year		$ 0
Balance at end of year			$ 0

Prepaid and Other Current Ass_3

Prepaid and Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Contract assets	$ 46,451	$ 39,048
Prepaid non-income taxes	25,251	23,069
Non-trade receivables	10,925	19,380
Prepaid income taxes	6,562	13,062
Other	28,492	26,034
Total	$ 117,681	$ 120,593

Accrued Expenses (Detail)

Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Payables and Accruals [Abstract]
Payroll and benefits	$ 92,305	$ 62,131
Accrued selling expenses	47,364	43,292
Hagen exit related accruals	24,593	0
Operating lease liabilities	21,774	21,128
Warranty	18,982	27,766
Contract liabilities	15,992	17,342
VAT and other non-income taxes	14,267	14,209
Freight	13,097	14,222
Interest	10,592	11,180
Tax Act - Transition Tax	6,172	6,172
Income taxes payable	5,683	304
Restructuring	2,595	3,325
Pension	1,514	1,350
Other	43,793	49,319
Total	$ 318,723	$ 271,740

Debt - Long Term Debt (Detail)

Debt - Long Term Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Debt Instrument [Line Items]
Long-term debt gross	$ 976,039	$ 1,113,224
Unamortized debt issuance expense	6,421	8,493
Long-term debt, net of unamortized issuance costs	969,618	1,104,731
Senior Unsecured 5.00% Due 2028
Debt Instrument [Line Items]
Long-term debt	600,000	600,000
Unamortized debt issuance expense	5,106	6,306
Amended Credit Facility, due 2022 | Secured Debt | 2017 Revolver borrowings
Debt Instrument [Line Items]
Incremental term loan commitment	376,039	513,224
Unamortized debt issuance expense	$ 1,315	$ 2,187

Debt - Additional Information (

Debt - Additional Information (Detail)

Dec. 11, 2019USD ($)

Aug. 04, 2017USD ($)

Dec. 31, 2019USD ($)

Mar. 31, 2021USD ($)

Mar. 31, 2020USD ($)

Mar. 31, 2019USD ($)

Dec. 29, 2019

Dec. 28, 2019

Sep. 30, 2019

Dec. 07, 2018USD ($)

Dec. 07, 2018CAD ($)

Apr. 23, 2015USD ($)

Debt Instrument [Line Items]

Increase in borrowing capacity

$ 325,000,000

Company owned capital stock percentage

65.00%

Weighted-average interest rate

3.50%

3.70%

Short term borrowing outstanding amount

$ 34,153,000

$ 46,544,000

Short-term debt, weighted-average interest rates

2.00%

3.00%

Payments of debt issuance costs

$ 1,393,000

Write off of deferred debt issuance costs

483,000

Amortization expense included in interest expense

$ 2,072,000

1,673,000

$ 1,316,000

Deferred financing fees, net of accumulated amortization

6,421,000

8,493,000

2027 Notes

Debt Instrument [Line Items]

Interest rate of debt instrument

4.375%

Long-term debt

$ 300,000,000

Proceeds from debt, net

$ 296,250,000

Debt issuance costs

4,607,000

2023 Notes

Debt Instrument [Line Items]

Interest rate of debt instrument

5.00%

Long-term debt

$ 300,000,000

2038 Notes

Debt Instrument [Line Items]

Interest paid

36,365,000

38,632,000

$ 29,552,000

Convertible Notes Payable

Debt Instrument [Line Items]

Available lines of credit

697,875,000

693,640,000

Stand by letters of credit

2,959,000

7,720,000

Uncommitted remaining borrowing capacity

122,303,000

$ 105,946,000

Maximum

Debt Instrument [Line Items]

Total purchase consideration

$ 250,000,000

2017 Revolver borrowings | Secured Debt

Debt Instrument [Line Items]

Maximum borrowing capacity

$ 299,105,000

Face value of debt instrument

$ 150,000,000

Available lines of credit

376,039,000

2017 Revolver borrowings | Revolving Credit Facility

Debt Instrument [Line Items]

Maximum borrowing capacity

600,000,000

100,000,000

Available lines of credit

0

Long term debt and capital lease obligation, current

$ 45,579,000

Amended 2017 Term Loan | Secured Debt

Debt Instrument [Line Items]

Maximum borrowing capacity

449,105,000

Amended 2017 Term Loan | Term Loan

Debt Instrument [Line Items]

Maximum borrowing capacity

99,105,000

$ 133,050,000

Amended 2017 Revolver | Secured Debt

Debt Instrument [Line Items]

Maximum borrowing capacity

$ 700,000,000

Debt Instrument Quarterly Installments Beginning December 31, 2018 Through December 30, 2019

Debt Instrument [Line Items]

Periodic payment

5,645,000

Debt Instrument Quarterly Installments Beginning December 31, 2019 Through December 30, 2020

Debt Instrument [Line Items]

Periodic payment

8,468,000

Debt Instrument Quarterly Installments Beginning December 31, 2020 Through September 29, 2022

Debt Instrument [Line Items]

Periodic payment

11,290,000

Debt Instrument Final Installments Payable On September 30, 2022

Debt Instrument [Line Items]

Periodic payment

$ 320,000,000

London Interbank Offered Rate (LIBOR) | 2017 Revolver And 2017 Term Loan

Debt Instrument [Line Items]

Interest at a floating rate

1.25%

London Interbank Offered Rate (LIBOR) | 2017 Revolver And 2017 Term Loan | Minimum

Debt Instrument [Line Items]

Interest at a floating rate

1.25%

London Interbank Offered Rate (LIBOR) | 2017 Revolver And 2017 Term Loan | Maximum

Debt Instrument [Line Items]

Interest at a floating rate

2.00%

Fed Funds Effective Rate Overnight Index Swap Rate | 2017 Revolver And 2017 Term Loan

Debt Instrument [Line Items]

Interest at a floating rate

0.50%

Eurodollar | 2017 Revolver And 2017 Term Loan

Debt Instrument [Line Items]

Interest at a floating rate

1.00%

CDOR Rate | 2017 Revolver And 2017 Term Loan

Debt Instrument [Line Items]

Interest at a floating rate

0.50%

Measurement Input, Maximum Leverage Ratio

Debt Instrument [Line Items]

Measurement input

4

3.50

4

3.50

Debt Instrument, Redemption, Period One | 2027 Notes

Debt Instrument [Line Items]

Redemption price, percentage

100.00%

Debt Instrument, Redemption, Period Two | 2027 Notes

Debt Instrument [Line Items]

Redemption price, percentage

100.00%

Debt Instrument, Redemption, Period Three | 2027 Notes

Debt Instrument [Line Items]

Redemption price, percentage

101.00%

Other Liabilities (Detail)

Other Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Other Liabilities Disclosure [Abstract]
Tax Act - Transition Tax	$ 53,045	$ 58,630
Operating lease liabilities	42,528	51,215
Pension	40,450	40,496
Warranty	39,980	35,759
Liability for uncertain tax positions	7,185	8,080
Contract liabilities	2,072	8,356
Other	10,508	11,280
Total	$ 195,768	$ 213,816

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Recurring - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	$ (1,556)	$ (2,432)
Lead forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(1,980)	(2,433)
Foreign currency forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	424	1
Quoted Price In Active Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	0	0
Quoted Price In Active Markets for Identical Assets (Level 1) | Lead forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	0	0
Quoted Price In Active Markets for Identical Assets (Level 1) | Foreign currency forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(1,556)	(2,432)
Significant Other Observable Inputs (Level 2) | Lead forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(1,980)	(2,433)
Significant Other Observable Inputs (Level 2) | Foreign currency forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	424	1
Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	0	0
Significant Unobservable Inputs (Level 3) | Lead forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	0	0
Significant Unobservable Inputs (Level 3) | Foreign currency forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	$ 0	$ 0

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	Nov. 11, 2020	Mar. 05, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Intangible asset impairment			$ 0	$ 4,549	$ 0
Fixed asset impairment	$ 3,975	$ 14,958
2027 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading of convertible notes, face value, disclosed as a percentage			102.00%	94.00%
2023 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading of convertible notes, face value, disclosed as a percentage			105.00%	97.00%
Fair Value, Measurements, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of fixed assets	$ 14,456		$ 242
Trademarks | EMEA
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of fixed assets				$ 1,700
Intangible asset impairment				$ 4,549
Royalty Rate | Trademarks | EMEA | Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Measurement inputs				0.0125
Discount Rate | Trademarks | EMEA | Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Measurement inputs				0.130

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Carrying Amounts and Estimated Fair Values of Company Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivatives assets, Carrying Amount	$ 0	$ 0
Derivatives assets, Fair Value	0	0
Derivatives liabilities, Carrying Amount	1,556	2,432
Derivatives liabilities, Fair Value	1,556	2,432
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Payable, Fair Value Disclosure	600,000	600,000
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Payable, Fair Value Disclosure	$ 621,000	$ 573,000

Derivative Financial Instrume_3

Derivative Financial Instruments - Additional Information (Detail) $ in Thousands, lb in Millions	12 Months Ended
	Mar. 31, 2021USD ($)lb	Mar. 31, 2020USD ($)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	$ 597
Lead forward contracts
Derivatives, Fair Value [Line Items]
Hedge forward contracts, maturity	1 year
Derivative, nonmonetary notional amount, mass | lb	54.5	35
Total purchase price of derivative	$ 50,567	$ 30,078
Designated as Hedging Instrument | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Notional amount	26,033	34,008
Not Designated as Hedging Instrument | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Notional amount	$ 28,995	$ 42,232

Derivative Financial Instrume_4

Derivative Financial Instruments - Fair Value of Derivative Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	$ 0	$ 0
Derivatives liabilities, Fair Value	1,556	2,432
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	524	0
Derivatives liabilities, Fair Value	1,980	2,807
Designated as Hedging Instrument | Prepaid and other current assets | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	524	0
Designated as Hedging Instrument | Accrued expenses | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivatives liabilities, Fair Value	0	374
Designated as Hedging Instrument | Accrued expenses | Lead forward contracts
Derivatives, Fair Value [Line Items]
Derivatives liabilities, Fair Value	1,980	2,433
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	0	375
Derivatives liabilities, Fair Value	100	0
Not Designated as Hedging Instrument | Prepaid and other current assets | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value	0	375
Not Designated as Hedging Instrument | Accrued expenses | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivatives liabilities, Fair Value	100	0
Not Designated as Hedging Instrument | Accrued expenses | Lead forward contracts
Derivatives, Fair Value [Line Items]
Derivatives liabilities, Fair Value	$ 0	$ 0

Derivative Financial Instrume_5

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, 2021	Mar. 31, 2020	Mar. 31, 2019
Derivatives, Fair Value [Line Items]
Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)	$ 332	$ (8,737)	$ (10,980)
Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	(7,903)	(1,151)	(15,281)
Lead forward contracts
Derivatives, Fair Value [Line Items]
Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)	202	(8,683)	(12,531)
Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Pretax Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)	130	(54)	1,551
Cost of Sales | Lead forward contracts
Derivatives, Fair Value [Line Items]
Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	(7,411)	(1,690)	(15,666)
Cost of Sales | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Pretax Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	$ (492)	$ 539	$ 385

Derivative Financial Instrume_6

Derivative Financial Instruments - Effect of Derivative Instruments (Detail) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ 430	$ (178)	$ (1,856)
Other (Income) Expense | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in Income on Derivatives	$ 430	$ (178)	$ (1,856)

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Current:
Federal	$ 12,591	$ 9,185	$ 6,377
State	4,133	2,561	5,027
Foreign	19,031	14,561	16,636
Total current income tax expense	35,755	26,307	28,040
Deferred income tax (benefit) expense
Federal	1,495	5,489	(5,031)
State	735	741	(669)
Foreign	(11,224)	(22,716)	(756)
Total deferred income tax (benefit) expense	(8,994)	(16,486)	(6,456)
Total income tax expense	$ 26,761	$ 9,821	$ 21,584

Income Taxes - Schedule of Earn

Income Taxes - Schedule of Earning Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
United States	$ 56,055	$ 36,193	$ 53,339
Foreign	114,080	110,744	128,872
Earnings before income taxes	$ 170,135	$ 146,937	$ 182,211

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Income Tax Contingency [Line Items]
Income taxes paid		$ 32,002,000	$ 48,653,000	$ 53,866,000
Net operating loss carryforwards carried forward indefinitely	$ 186,816,000
Net operating loss carryforwards subject to expiration	48,409,000
Valuation allowance	31,928,000	20,951,000	17,519,000	$ 15,255,000
Increase (decrease) in deferred tax asset	(940,000)	(229,000)	(1,772,000)
Income tax expense	26,761,000	$ 9,821,000	$ 21,584,000
Effective income tax rates		15.70%	6.70%	11.90%
Deferred tax asset		$ 22,500,000
Foreign pre-tax income	$ 114,080,000	$ 110,744,000	$ 128,872,000
Foreign pre-tax income, percent	6.80%	(7.40%)	12.30%
Tax rate of Swiss subsidiary	8.00%	3.00%	4.00%
Blended rate	21.00%
Undistributed earnings of foreign subsidiaries		$ 1,591,000,000	$ 1,376,000,000
Unrecognized tax benefits	$ 6,785,000	7,795,000	$ 20,165,000	$ 1,568,000
Estimated change in unrecognized tax benefit in fiscal 2015	1,850,000
Tax related interest and penalties	400,000	285,000
Federal
Income Tax Contingency [Line Items]
United States federal net operating loss carryforwards	1,078,000
Valuation allowance	0	0
Foreign
Income Tax Contingency [Line Items]
United States federal net operating loss carryforwards	235,225,000
Valuation allowance	31,242,000	20,055,000
Increase (decrease) in deferred tax asset	11,187,000
Income tax expense	1,883,000
State
Income Tax Contingency [Line Items]
United States federal net operating loss carryforwards	28,955,000
Valuation allowance	686,000	$ 896,000
Increase to Income Tax Expense (Benefit) | Foreign
Income Tax Contingency [Line Items]
Increase (decrease) in deferred tax asset	5,743,000
Purchase Accounting Adjustment | Foreign
Income Tax Contingency [Line Items]
Increase (decrease) in deferred tax asset	6,384,000
Foreign Currency Translation Adjustment And Offset Adjustment To Net Operating Losses | Foreign
Income Tax Contingency [Line Items]
Increase (decrease) in deferred tax asset	$ (940,000)

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Deferred tax assets:
Accounts receivable	$ 2,029	$ 1,110
Inventories	8,831	5,010
Net operating loss carryforwards	62,663	44,340
Lease liabilities	15,685	18,168
Accrued expenses	36,775	26,113
Other assets	18,173	19,793
Gross deferred tax assets	144,156	114,534
Less valuation allowance	(31,928)	(20,951)	$ (17,519)	$ (15,255)
Total deferred tax assets	112,228	93,583
Deferred tax liabilities:
Property, plant and equipment	38,364	30,229
Lease Right-of-use assets	15,685	18,168
Intangible assets	66,743	66,529
Other liabilities	2,636	1,217
Total deferred tax liabilities	123,428	116,143
Net deferred tax liabilities	$ (11,200)	$ (22,560)

Income Taxes - Schedule of Valu

Income Taxes - Schedule of Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Deferred Tax Asset, Valuation Allowance [Roll Forward]
Balance at Beginning of Period	$ 20,951	$ 17,519	$ 15,255
Additions Charged to Expense	8,437	7,494	2,978
Valuation Allowance Reversal	(2,904)	(3,145)	(99)
Business Combination Adjustments	6,384	(688)	1,157
Other	(940)	(229)	(1,772)
Balance at End of Period	$ 31,928	$ 20,951	$ 17,519

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Taxes at Statutory Rate (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
United States statutory income tax expense		$ 35,729	$ 30,857	$ 38,264
Impact of Tax Act	$ 21,000	0	0	(13,483)
State income taxes, net of federal effect		4,000	2,764	3,285
Nondeductible expenses and other		5,273	5,953	4,378
Legal proceedings charge - European Competition Investigations		0	0	2,405
Net effect of GILTI, FDII, BEAT		1,985	3,025	2,320
Goodwill impairment - See Note 7		0	10,714	0
Effect of foreign operations		(20,035)	(17,605)	(16,763)
Valuation allowance		5,533	4,349	2,879
Switzerland Tax Reform		(1,883)	(26,846)	0
Research and Development Credit		(3,841)	(3,390)	(1,701)
Total income tax expense		$ 26,761	$ 9,821	$ 21,584

Income Taxes - Reconciliation_2

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Reconciliation of Unrecognized Tax Benefits
Unrecognized tax benefits, beginning balance	$ 7,795	$ 20,165	$ 1,568
Increases related to current year tax positions	346	598	129
Increases related to the Alpha acquisition	0	769	7,840
Increases related to prior year tax positions	325	0	11,463
Decreases related to prior tax positions due to foreign currency translation	0	(11,463)	(544)
Decreases related to prior year tax positions	0	0	(93)
Lapse of statute of limitations	(1,681)	(2,274)	(198)
Unrecognized tax benefits, ending balance	$ 6,785	$ 7,795	$ 20,165

Retirement Plans - Net Periodic

Retirement Plans - Net Periodic Pension Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 0	$ 0
Interest cost	533	616	631
Expected return on plan assets	(272)	(448)	(514)
Amortization and deferral	476	188	184
Net periodic benefit cost	737	356	301
International Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	993	906	997
Interest cost	1,388	1,485	1,831
Expected return on plan assets	(1,899)	(2,136)	(2,151)
Amortization and deferral	1,053	910	1,520
Net periodic benefit cost	$ 1,535	$ 1,165	$ 2,197

Retirement Plans - Change in Pr

Retirement Plans - Change in Projected Benefit Obligations and Change in Plan Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
United States Plans
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at the beginning of the period	$ 18,111	$ 16,647
Service cost	0	0	$ 0
Interest cost	533	616	631
Benefits paid, inclusive of plan expenses	(802)	(1,132)
Plan curtailments and settlements	0	0
Actuarial losses (gains)	(36)	1,980
Foreign currency translation adjustment	0	0
Benefit obligation at the end of the period	17,806	18,111	16,647
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at the beginning of the period	12,036	13,763
Actual return on plan assets	4,379	(649)
Employer contributions	652	54
Benefits paid, inclusive of plan expenses	(802)	(1,132)
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	16,265	12,036	13,763
Funded status deficit	(1,541)	(6,075)
International Plans
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at the beginning of the period	68,602	75,038
Service cost	993	906	997
Interest cost	1,388	1,485	1,831
Benefits paid, inclusive of plan expenses	(2,087)	(2,262)
Plan curtailments and settlements	(91)	(678)
Actuarial losses (gains)	7,761	(3,024)
Foreign currency translation adjustment	6,686	(2,863)
Benefit obligation at the end of the period	83,252	68,602	75,038
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at the beginning of the period	32,831	36,791
Actual return on plan assets	6,272	(1,605)
Employer contributions	1,869	2,098
Benefits paid, inclusive of plan expenses	(2,087)	(2,262)
Defined Benefit Plan, Settlements and Curtailments, Plan Assets	(91)	(482)
Foreign currency translation adjustment	4,050	(1,709)
Fair value of plan assets at the end of the period	42,844	32,831	$ 36,791
Funded status deficit	$ (40,408)	$ (35,771)

Retirement Plans - Amounts Reco

Retirement Plans - Amounts Recognized in Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan amounts recognized in balance sheet	$ (41,949)	$ (41,846)
Non current assets
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan amounts recognized in balance sheet	15	0
Accrued expenses
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan amounts recognized in balance sheet	(1,514)	(1,350)
Other liabilities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan amounts recognized in balance sheet	$ (40,450)	$ (40,496)

Retirement Plans - Pension Comp

Retirement Plans - Pension Components Before Tax and Related Changes Net of Tax Recognized in AOCI (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Retirement Benefits [Abstract]
Prior service cost	$ (230)	$ (258)	$ (307)
Net loss	(25,450)	(25,796)	(24,051)
Net amount recognized	$ (25,680)	$ (26,054)	$ (24,358)

Retirement Plans - Summary Chan

Retirement Plans - Summary Changes in Plan Assets and Benefit Obligations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Changes in plan assets and benefit obligations:
New prior service cost	$ 0	$ 0	$ 0
Net loss (gain) arising during the year	(753)	3,793	(99)
Effect of exchange rates on amounts included in AOCI	1,909	(804)	(1,984)
Amounts recognized as a component of net periodic benefit costs:
Amortization of prior service cost	(46)	(43)	(45)
Amortization or settlement recognition of net loss	(1,484)	(1,250)	(1,659)
Total recognized in other comprehensive (income) loss	$ (374)	$ 1,696	$ (3,787)

Retirement Plans - Summary of R

Retirement Plans - Summary of Recognized Components of Net Periodic Pension Cost Included in Accumulated Other Comprehensive Income (Detail) $ in Thousands	Mar. 31, 2021USD ($)
Retirement Benefits [Abstract]
Prior service cost	$ (46)
Net loss	(1,163)
Net amount expected to be recognized	$ (1,209)

Retirement Plans - Summary of A

Retirement Plans - Summary of Accumulated Benefit Obligation Related to All Defined Pension Plans (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 17,806	$ 18,111
Projected benefit obligation	17,806	18,111
Fair value of plan assets	16,265	12,036
United States Plans | Unfunded defined benefit plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	0	0
Projected benefit obligation	0	0
United States Plans | Defined benefit plans with an accumulated benefit obligation in excess of the fair value of plan assets
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	17,806	18,111
Fair value of plan assets	16,265	12,036
Accumulated benefit obligation	17,806	18,111
International Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	78,360	65,336
Projected benefit obligation	82,814	68,602
Fair value of plan assets	42,390	32,831
International Plans | Unfunded defined benefit plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	31,970	28,926
Projected benefit obligation	34,932	30,773
International Plans | Defined benefit plans with an accumulated benefit obligation in excess of the fair value of plan assets
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	82,814	68,602
Fair value of plan assets	42,390	32,831
Accumulated benefit obligation	$ 77,928	$ 65,336

Retirement Plans - Significant

Retirement Plans - Significant Assumptions Used to Determine Net Periodic Benefit Cost (Detail)	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.00%	3.80%	3.90%
Expected return on plan assets	6.00%	6.30%	6.30%
Minimum | International Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	1.30%	1.00%	1.40%
Expected return on plan assets	3.80%	4.30%	4.10%
Rate of compensation increase	2.00%	2.00%	1.80%
Maximum | International Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.30%	2.70%	3.30%
Expected return on plan assets	5.50%	6.00%	6.00%
Rate of compensation increase	3.50%	4.00%	4.00%

Retirement Plans - Significan_2

Retirement Plans - Significant Assumptions Used to Determine Projected Benefit Obligations (Detail)	Mar. 31, 2021	Mar. 31, 2020
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.00%	3.00%
International Plans | Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	0.50%	1.30%
Rate of compensation increase	1.50%	2.00%
International Plans | Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.30%	2.30%
Rate of compensation increase	4.00%	3.50%

Retirement Plans - Additional I

Retirement Plans - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Expected cash contributions to pension plans in 2014	$ 2,578
Defined Contribution Pension
Defined Benefit Plan Disclosure [Line Items]
Employer expenses	16,460	$ 15,835	$ 12,078
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Employer expenses	652	54
International Plans
Defined Benefit Plan Disclosure [Line Items]
Employer expenses	$ 1,869	$ 2,098
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 P

Retirement Plans - Summary of Pension Plan Investments Measured at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	$ 16,265	$ 12,036	$ 13,763
International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	42,844	32,831	$ 36,791
Quoted Price In Active Markets for Identical Assets (Level 1) | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	16,265	12,036
Quoted Price In Active Markets for Identical Assets (Level 1) | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	81	141
Significant Other Observable Inputs (Level 2) | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
Significant Other Observable Inputs (Level 2) | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	42,763	32,690
Significant Unobservable Inputs (Level 3) | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
Significant Unobservable Inputs (Level 3) | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
Cash and Cash Equivalents | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	1,454	1,221
Cash and Cash Equivalents | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	81	141
Cash and Cash Equivalents | Quoted Price In Active Markets for Identical Assets (Level 1) | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	1,454	1,221
Cash and Cash Equivalents | Quoted Price In Active Markets for Identical Assets (Level 1) | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	81	141
Cash and Cash Equivalents | Significant Other Observable Inputs (Level 2) | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
Cash and Cash Equivalents | Significant Other Observable Inputs (Level 2) | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
Cash and Cash Equivalents | Significant Unobservable Inputs (Level 3) | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
Cash and Cash Equivalents | Significant Unobservable Inputs (Level 3) | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
US Equity Securities | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	10,435	6,860
US Equity Securities | Quoted Price In Active Markets for Identical Assets (Level 1) | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	10,435	6,860
US Equity Securities | Significant Other Observable Inputs (Level 2) | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
US Equity Securities | Significant Unobservable Inputs (Level 3) | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
International Equity Securities | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	28,144	20,059
International Equity Securities | Quoted Price In Active Markets for Identical Assets (Level 1) | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
International Equity Securities | Significant Other Observable Inputs (Level 2) | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	28,144	20,059
International Equity Securities | Significant Unobservable Inputs (Level 3) | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
Fixed Income Funds | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	4,376	3,955
Fixed Income Funds | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	14,619	12,631
Fixed Income Funds | Quoted Price In Active Markets for Identical Assets (Level 1) | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	4,376	3,955
Fixed Income Funds | Quoted Price In Active Markets for Identical Assets (Level 1) | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
Fixed Income Funds | Significant Other Observable Inputs (Level 2) | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
Fixed Income Funds | Significant Other Observable Inputs (Level 2) | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	14,619	12,631
Fixed Income Funds | Significant Unobservable Inputs (Level 3) | United States Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	0	0
Fixed Income Funds | Significant Unobservable Inputs (Level 3) | International Plans
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value Measurement	$ 0	$ 0

Retirement Plans - Summary of E

Retirement Plans - Summary of Estimated Future Benefit Payments (Detail) $ in Thousands	Mar. 31, 2021USD ($)
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2022	$ 3,181
2023	3,253
2024	3,172
2025	3,794
2026	4,073
Years 2027-2031	$ 22,308

Stockholders_ Equity - Addition

Stockholders’ Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Dec. 07, 2018	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		1,000,000	1,000,000
Preferred stock, par value (usd per share)		$ 0.01	$ 0.01
Preferred stock, shares issued (in shares)		0	0
Preferred stock, shares outstanding (in shares)		0	0
Number of shares of common stock purchased		0	581,140	726,347
Repurchased common stock value			$ 34,561	$ 56,436
Treasury stock, shares (in shares)		12,799,790	12,791,503
Shares issued in ESPP (USD per share)		$ 62.55	$ 62.55
Alpha
Class of Stock [Line Items]
Initial purchase consideration	$ 750,000
Payments to acquire businesses	$ 650,000
Shares issued in acquisition (USD per share)	$ 84.92
Fair value of shares issued for net assets acquired	$ 93,268
Common Stock | Alpha
Class of Stock [Line Items]
Shares issued in acquisition (in shares)	1,177,630
Shares issued in employee stock purchase plan (in shares)		13,465	17,410	3,256

Stockholders' Equity - Change i

Stockholders' Equity - Change in Number of Shares of Common Stock Outstanding (Detail) - shares	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares outstanding, beginning balance	42,323,305	42,620,750	41,915,000
Purchase of treasury stock	0	(581,140)	(726,347)
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	429,715	283,695	254,467
Shares outstanding, ending balance	42,753,020	42,323,305	42,620,750

Stockholders' Equity - Componen

Stockholders' Equity - Components of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ (215,006)	$ (142,682)	$ (41,717)
Before Reclassifications	91,923	(74,019)	(114,029)
Amount Reclassified from AOCI	7,200	1,695	13,064
Ending Balance	(115,883)	(215,006)	(142,682)
Pension funded status adjustment
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(22,794)	(20,791)	(22,503)
Before Reclassifications	680	(2,819)	339
Amount Reclassified from AOCI	1,167	816	1,373
Ending Balance	(20,947)	(22,794)	(20,791)
Net unrealized gain (loss) on derivative instruments
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(5,923)	(130)	(3,425)
Before Reclassifications	250	(6,672)	(8,396)
Amount Reclassified from AOCI	6,033	879	11,691
Ending Balance	360	(5,923)	(130)
Foreign currency translation adjustment
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(186,289)	(121,761)	(15,789)
Before Reclassifications	90,993	(64,528)	(105,972)
Amount Reclassified from AOCI	0	0	0
Ending Balance	$ (95,296)	$ (186,289)	$ (121,761)

Stockholders' Equity - Reclassi

Stockholders' Equity - Reclassification from Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2021	Jan. 03, 2021	Oct. 04, 2020	Jul. 05, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Cost of goods sold									$ 2,238,782	$ 2,301,148	$ 2,104,612
Income tax expense									26,761	9,821	21,584
Net earnings attributable to EnerSys stockholders	$ (33,836)	$ (38,624)	$ (35,731)	$ (35,183)	$ 1,523	$ (27,305)	$ (62,698)	$ (48,636)	(143,374)	(137,116)	(160,239)
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									7,903	1,151	15,281
Income tax expense									(1,870)	(272)	(3,590)
Net earnings attributable to EnerSys stockholders									6,033	879	11,691
Pension funded status adjustment | Reclassification out of Accumulated Other Comprehensive Income
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Income tax expense									(362)	(282)	(331)
Prior service costs and deferrals									1,529	1,098	1,704
Net earnings attributable to EnerSys stockholders									$ 1,167	$ 816	$ 1,373

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants	3,206,045
Stock options granted	295,068	284,109	192,700
Stock-based compensation expense	$ 3,514	$ 565	$ 3,251
Stock-based compensation expense, net of tax	$ 368	$ 2,996	$ 634
Market price per unit of stock award	$ 71.53	$ 58.05	$ 75.32
Unrecognized compensation expense associated with non-vested incentive awards outstanding	$ 49,054
Nonvested stock, weighted average remaining contractual term	29 months
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market price per unit of stock award	$ 71.53
Stock unit grant during period	324,262
Restricted Shares Restricted Stock Units and Market Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 16,303	$ 17,784	$ 19,357
Stock unit grant during period	1,435	1,147	1,441
Equity-based compensation expense, tax benefit	$ 2,121	$ 2,544	$ 3,085
Non Employee Directors | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted (in shares)	39,726	40,462	35,065
Market price per unit of stock award	$ 39.93	$ 39.74	$ 46.30
Management | Nonqualified Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted	295,068
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	$ 75.39	$ 57.75	$ 75.17
Stock unit grant during period	283,101	301,321	204,599
Management | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market price per unit of stock award		$ 50.69	$ 68.48
Stock unit grant during period		62,512	45,883
Management | Market Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market price per unit of stock award		$ 62.05	$ 86.23
Stock unit grant during period		51,063	36,646
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 Stock-

Stock Based Compensation Stock-Based Compensation - Summary of Assumptions Used for Market Share Units (Details)	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Market Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.39%	1.52%	2.77%
Dividend yield	0.93%	1.21%	0.93%
Expected life (years)	6 years	6 years	6 years
Volatility	37.20%	29.10%	26.80%
Performance Market Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate		1.50%	2.66%
Dividend yield		0.00%	0.00%
Expected life (years)		3 years	3 years
Volatility		34.39%	26.41%

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Number of options
Number of Options outstanding, Beginning Balance	791,582	554,906	545,590
Number of Options, Granted	295,068	284,109	192,700
Number of Options, Exercised	(247,975)	(24,826)	(171,630)
Number of Options, Forfeited	(34,854)	(22,607)	(11,754)
Number of Options, Expired	(4,320)	0	0
Number of Options outstanding, Ending Balance	799,501	791,582	554,906	545,590
Number of Options, Exercisable	291,440
Number of Options, Vested and Expected to Vest	782,935
Options outstanding, Weighted Average Remaining Contract Term
Options outstanding, Weighted Average Remaining Contract Term (Years)	7 years 9 months 18 days	7 years 9 months 18 days	8 years	8 years 4 months 24 days
Options exercisable, Weighted Average Remaining Contract Term (Years)	6 years 1 month 6 days
Options vested and expected to vest, Weighted Average Remaining Contract Term (Years)	7 years 9 months 18 days
Weighted average exercise price
Options outstanding, Weighted Average Exercise Price, Beginning Balance (in dollars per share)	$ 67.55	$ 72.31	$ 68.65
Weighted Average Exercise Price, Granted (in dollars per share)	79.62	57.75	75.17
Weighted Average Exercise Price, Exercised (in dollars per share)	66.11	57.60	63.66
Weighted Average Exercise Price, Expired (in dollars per share)	69.20	72.19	75.17
Weighted Average Exercise Price, Forfeited (in dollars per share)	80.25		0
Options outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)	72.31	$ 67.55	$ 72.31	$ 68.65
Options exercisable, Weighted Average Exercise Price (in dollars per share)	73.25
Weighted Average Exercise Price, Vested and Expected to Vest (in dollars per share)	$ 72.28
Aggregate intrinsic value
Options outstanding, Aggregate Intrinsic Value, Beginning Balance	$ 0	$ 1,040	$ 2,679
Options exercised, aggregate intrinsic value	6,382	383	2,707
Options forfeited, aggregate intrinsic value	290	88	0
Options expired, aggregate intrinsic value	0	0	0
Options outstanding, Aggregate Intrinsic Value, Ending Balance	14,781	$ 0	$ 1,040	$ 2,679
Options exercisable, Aggregate Intrinsic Value	5,114
Options vested and expected to vest, aggregate intrinsic value	$ 14,497

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Information Regarding Stock Options Outstanding and Exercisable (Detail)	12 Months Ended
	Mar. 31, 2021$ / sharesshares
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Number of Options | shares	799,501
Weighted- Average Remaining Contractual Life (Years)	7 years 9 months 18 days
Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 72.31
$57.60-$60.00
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Number of Options | shares	231,025
Weighted- Average Remaining Contractual Life (Years)	7 years 10 months 24 days
Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 57.73
$60.01-$70.00
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Number of Options | shares	56,530
Weighted- Average Remaining Contractual Life (Years)	3 years 10 months 24 days
Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 68.78
$70.01-$83.14
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Number of Options | shares	511,946
Weighted- Average Remaining Contractual Life (Years)	8 years 2 months 12 days
Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 79.28

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Changes in Restricted Stock Units and Market Share Units (Detail) - $ / shares	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Granted	$ 71.53	$ 58.05	$ 75.32
Restricted Stock Units (RSUs)
Number of RSU and MSU
Number of RSU and MSU, Non-vested awards, Beginning Balance	880,335
Number of RSU and MSU, Granted	324,262
Number of RSU and MSU, Stock dividend	8,125
Number of RSU and MSU, Performance factor	0
Number of RSU and MSU, Vested	(279,995)
Number of RSU and MSU, cancelled	(52,443)
Number of RSU and MSU, Non-vested awards, Ending Balance	880,284	880,335
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance	$ 55.61
Weighted Average Grant Date Fair Value, Granted	71.53
Weighted Average Grant Date Fair Value, Stock dividend	57.69
Weighted Average Grant Date Fair Value, Performance factor	0
Weighted Average Grant Date Fair Value, Vested	58.01
Weighted Average Grant Date Fair Value, Canceled	68.94
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance	$ 60.07	$ 55.61
Market Share Unit Number (MSU)
Number of RSU and MSU
Number of RSU and MSU, Non-vested awards, Beginning Balance	208,720
Number of RSU and MSU, Granted	37
Number of RSU and MSU, Stock dividend	1,165
Number of RSU and MSU, Performance factor	0
Number of RSU and MSU, Vested	(65,096)
Number of RSU and MSU, cancelled	(18,866)
Number of RSU and MSU, Non-vested awards, Ending Balance	125,960	208,720
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance	$ 80.78
Weighted Average Grant Date Fair Value, Granted	79.51
Weighted Average Grant Date Fair Value, Stock dividend	83.15
Weighted Average Grant Date Fair Value, Performance factor	0
Weighted Average Grant Date Fair Value, Vested	71.17
Weighted Average Grant Date Fair Value, Canceled	98.88
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance	$ 83.48	$ 80.78
Performance condition-based Share Units (PSU)
Number of RSU and MSU
Number of RSU and MSU, Non-vested awards, Beginning Balance	101,130
Number of RSU and MSU, Granted	0
Number of RSU and MSU, Stock dividend	917
Number of RSU and MSU, Performance factor	0
Number of RSU and MSU, Vested	0
Number of RSU and MSU, cancelled	(3,701)
Number of RSU and MSU, Non-vested awards, Ending Balance	98,346	101,130
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance	$ 57.49
Weighted Average Grant Date Fair Value, Granted	0
Weighted Average Grant Date Fair Value, Stock dividend	57.52
Weighted Average Grant Date Fair Value, Performance factor	0
Weighted Average Grant Date Fair Value, Vested	0
Weighted Average Grant Date Fair Value, Canceled	56.04
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance	$ 57.55	$ 57.49

Earnings Per Share - Weighted A

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, 2021	Jan. 03, 2021	Oct. 04, 2020	Jul. 05, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Net earnings attributable to EnerSys stockholders	$ 33,836	$ 38,624	$ 35,731	$ 35,183	$ (1,523)	$ 27,305	$ 62,698	$ 48,636	$ 143,374	$ 137,116	$ 160,239
Basic (in shares)									42,548,449	42,411,834	42,335,023
Dilutive effect of:
Common shares from exercise and lapse of equity awards, net of shares assumed reacquired (in shares)									675,954	484,941	673,929
Diluted weighted-average number of common shares outstanding (in shares)									43,224,403	42,896,775	43,008,952
Basic earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.79	$ 0.91	$ 0.84	$ 0.83	$ (0.04)	$ 0.65	$ 1.48	$ 1.14	$ 3.37	$ 3.23	$ 3.79
Diluted earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.78	$ 0.89	$ 0.83	$ 0.82	$ (0.04)	$ 0.64	$ 1.47	$ 1.13	$ 3.32	$ 3.20	$ 3.73
Anti-dilutive equity awards not included in diluted weighted-average common shares (in shares)									281,483,000	698,546,000	355,728,000

Commitments, Contingencies an_2

Commitments, Contingencies and Litigation - Additional Information (Detail) $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2016USD ($)	Mar. 31, 2021USD ($)Employee
Commitments, Contingencies And Litigation [Line Items]
Company number of employees | Employee		11,100
Percentage of employees covered by collective bargaining agreements		27.00%
Percentage of collective bargaining agreements that expire in next twelve months		11.00%
Average term of collective bargaining agreements		2 years
Longest term of collective bargaining agreements		3 years 6 months
Belgium Anti-Competition Proceeding
Commitments, Contingencies And Litigation [Line Items]
Penalties paid relating to anti-competition investigations	$ 1,962
Legal proceedings charge		$ 2,402

Restructuring, Exit and Other_2

Restructuring, Exit and Other Charges - Additional Information (Details) $ in Thousands	Nov. 10, 2020USD ($)Employee	Mar. 31, 2021USD ($)	Jan. 03, 2021USD ($)	Oct. 04, 2020USD ($)	Jul. 05, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2021USD ($)Employee	Mar. 31, 2020USD ($)Employee	Mar. 31, 2019USD ($)	Mar. 31, 2021USD ($)
Restructuring Cost and Reserve [Line Items]
Expected cost remaining		$ 7,424								$ 7,424			$ 7,424
Expected reduction in number of employees | Employee											160
Write-off of assets relating to restructuring and other exit charges										10,231	$ 10,986	$ 26,308
Restructuring and other exit charges		20,672	$ 15,196	$ 3,119	$ 1,387	$ 2,695	$ 9,417	$ 6,282	$ 2,372	$ 40,374	20,766	34,709
Gain on sale of certain licenses and assets			4,397
Restructuring Related to Sale of Geräte- und Akkumulatorenwerk Zwickau GmbH
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											4,930
Restructuring Charges Relating to Dissolving Joint Venture in Tunisia
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											957
Restructuring Related to Improving Profitability in India | Asia
Restructuring Cost and Reserve [Line Items]
Write-off of assets relating to restructuring and other exit charges											660
Energy Systems
Restructuring Cost and Reserve [Line Items]
Expected reduction in number of employees | Employee										47
Restructuring and other exit charges										$ 3,187	7,284	10,593
Motive Power
Restructuring Cost and Reserve [Line Items]
Expected reduction in number of employees | Employee										32
Restructuring and other exit charges										$ 36,798	2,021	5,751
Specialty
Restructuring Cost and Reserve [Line Items]
Expected remaining restructuring charges		169								169			169
Restructuring and other exit charges										389	6,020	18,365
Cash Charges | Energy Systems
Restructuring Cost and Reserve [Line Items]
Expected remaining restructuring charges		3,187								3,187			3,187
Cash Charges | Motive Power
Restructuring Cost and Reserve [Line Items]
Expected remaining restructuring charges		4,012								4,012			4,012
Non Cash Charges | Restructuring Related to Improving Profitability in India | Asia | Cost of Sales
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											526
Employee Severance
Restructuring Cost and Reserve [Line Items]
Exit charges										33,006	9,780	24,086
Restructuring and other exit charges										40,374	20,766	34,709
Employee Severance | Energy Systems
Restructuring Cost and Reserve [Line Items]
Exit charges										0	526	5,477
Restructuring and other exit charges										3,187	7,334	10,592
Employee Severance | Motive Power
Restructuring Cost and Reserve [Line Items]
Exit charges										32,786	5,541	957
Restructuring and other exit charges										36,798	7,401	5,752
Employee Severance | Specialty
Restructuring Cost and Reserve [Line Items]
Exit charges										220	3,713	17,652
Restructuring and other exit charges										389	6,031	18,365
Closure of Facility in Hagen, Germany
Restructuring Cost and Reserve [Line Items]
Expected remaining restructuring charges	$ 60,000
Expected reduction in number of employees | Employee	200
Closure of Facility in Hagen, Germany | Cash Charges
Restructuring Cost and Reserve [Line Items]
Expected remaining restructuring charges	$ 40,000
Closure of Facility in Hagen, Germany | Non Cash Charges
Restructuring Cost and Reserve [Line Items]
Expected remaining restructuring charges	$ 20,000	7,946								7,946			7,946
Closure of Facility in Hagen, Germany | Employee Severance
Restructuring Cost and Reserve [Line Items]
Write-off of assets relating to restructuring and other exit charges										23,331
Closure of Facility in Vijayawada, India | Employee Severance
Restructuring Cost and Reserve [Line Items]
Exit charges										1,509
Closure Of Facility In Targovishte, Bulgaria
Restructuring Cost and Reserve [Line Items]
Expected cost remaining												26,000
Restructuring and other exit charges										220	5,123	$ 20,242
Strategy to Exit Manufacture of Batteries for Diesel-Electric Submarines
Restructuring Cost and Reserve [Line Items]
Proceeds from sale of assets											2,031
Gain on sale of certain licenses and assets											892
Fixed Asset Write-Off, Kentucky and Tennessee Plants
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											5,441
Richmond Kentucky Battery Formation Area Fire
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges						5							46,117
Gain on sale of certain licenses and assets										4,397
Prepaid insurance		$ 21,617				$ 12,000				21,617	12,000		$ 21,617
Restructuring charges, cash charges related to employee severance and other charges										7,500	5,000
Richmond Kentucky Battery Formation Area Fire | Write-Offs for Damages, Cleanup, Asset Replacement, and Other
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges											$ 17,037
Richmond Kentucky Battery Formation Area Fire | Cleanup
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges										16,580
Richmond Kentucky Battery Formation Area Fire | Business Interruption Claim
Restructuring Cost and Reserve [Line Items]
Restructuring charges, cash charges related to employee severance and other charges			$ 2,344	$ 1,456	$ 3,700					$ 12,500

Restructuring, Exit and Other_3

Restructuring, Exit and Other Charges - Acquisition and Non-Acquisition Related Restructuring Reserve (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended			24 Months Ended
	Mar. 31, 2021	Jan. 03, 2021	Oct. 04, 2020	Jul. 05, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2021
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges	$ 20,672	$ 15,196	$ 3,119	$ 1,387	$ 2,695	$ 9,417	$ 6,282	$ 2,372	$ 40,374	$ 20,766	$ 34,709
Energy Systems
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges									3,187	7,284	10,593
Motive Power
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges									36,798	2,021	5,751
Specialty
Restructuring Cost and Reserve [Line Items]
Restructuring and other exit charges									389	6,020	18,365
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring charges									7,368	10,986	10,623
Exit charges									33,006	9,780	24,086
Restructuring and other exit charges									40,374	20,766	34,709
Employee Severance | Energy Systems
Restructuring Cost and Reserve [Line Items]
Restructuring charges									3,187	6,808	5,115
Exit charges									0	526	5,477
Restructuring and other exit charges									3,187	7,334	10,592
Employee Severance | Motive Power
Restructuring Cost and Reserve [Line Items]
Restructuring charges									4,012	1,860	4,795
Exit charges									32,786	5,541	957
Restructuring and other exit charges									36,798	7,401	5,752
Employee Severance | Specialty
Restructuring Cost and Reserve [Line Items]
Restructuring charges									169	2,318	713
Exit charges									220	3,713	17,652
Restructuring and other exit charges									389	6,031	18,365
Non-Acquisition Related Restructuring Plans
Restructuring Reserve [Roll Forward]
Beginning balance				3,325				2,952	3,325	2,952	2,909	$ 2,952
Accrued									7,368	10,797	8,193
Costs incurred									(8,381)	(10,174)	(7,979)
Foreign currency impact and other									283	(250)	(171)
Ending balance	2,595				3,325				2,595	3,325	2,952	2,595
Non-Acquisition Related Restructuring Plans | Employee Severance
Restructuring Reserve [Roll Forward]
Beginning balance				3,325				2,356	3,325	2,356	2,893	2,356
Accrued									6,537	10,395	6,554
Costs incurred									(7,550)	(9,179)	(6,893)
Foreign currency impact and other									283	(247)	(198)
Ending balance	2,595				3,325				2,595	3,325	2,356	2,595
Non-Acquisition Related Restructuring Plans | Other
Restructuring Reserve [Roll Forward]
Beginning balance				$ 0				$ 596	0	596	16	596
Accrued									831	402	1,639
Costs incurred									(831)	(995)	(1,086)
Foreign currency impact and other									0	(3)	27
Ending balance	$ 0				$ 0				$ 0	$ 0	$ 596	$ 0

Warranty (Detail)

Warranty (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Product Warranty Accrual [Roll Forward]
Balance at beginning of year	$ 63,525	$ 54,568	$ 50,602
Current year provisions	27,645	27,622	23,679
Costs incurred	(34,346)	(25,778)	(25,053)
Warranty reserves of acquired businesses	0	6,995	7,535
Foreign currency translation adjustment	2,138	118	(2,195)
Balance at end of year	$ 58,962	$ 63,525	$ 54,568

Other (Income) Expense, Net (De

Other (Income) Expense, Net (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Other Income and Expenses [Abstract]
Foreign exchange transaction losses (gains)	$ 6,696	$ 264	$ (3,044)
Non-service components of pension expense	1,279	615	1,502
Other	(171)	(1,294)	928
Total	$ 7,804	$ (415)	$ (614)

Business Segments - Additional

Business Segments - Additional Information (Detail) $ in Thousands	12 Months Ended
	Mar. 31, 2021USD ($)segmentCountry	Mar. 31, 2020USD ($)	Mar. 31, 2019
Segment Reporting Information [Line Items]
Number of operating segments | segment	3
Number of reportable segments | segment	3
Operations in number of countries | Country	100
Property, plant, and equipment, net	$ 497,056	$ 480,014
United States
Segment Reporting Information [Line Items]
Percentage of sales to customers	59.80%	58.10%	48.50%
Property, plant, and equipment, net	$ 291,578	$ 277,358
Energy Systems
Segment Reporting Information [Line Items]
Property, plant, and equipment, net	224,513	182,122
Motive Power
Segment Reporting Information [Line Items]
Property, plant, and equipment, net	152,468	153,438
Specialty
Segment Reporting Information [Line Items]
Property, plant, and equipment, net	$ 120,075	$ 144,454

Business Segments - Schedule of

Business Segments - Schedule of Financial Information by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2021	Jan. 03, 2021	Oct. 04, 2020	Jul. 05, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Net sales	$ 813,539	$ 751,067	$ 708,402	$ 704,924	$ 781,803	$ 763,698	$ 762,137	$ 780,230	$ 2,977,932	$ 3,087,868	$ 2,808,017
Operating earnings	51,669	56,071	55,415	53,220	20,065	43,084	58,710	68,336	216,375	190,195	212,465
Inventory step up to fair value relating to acquisitions									0	(1,854)	(10,379)
Restructuring and other exit charges	(20,672)	$ (15,196)	$ (3,119)	$ (1,387)	(2,695)	$ (9,417)	$ (6,282)	$ (2,372)	(40,374)	(20,766)	(34,709)
Impairment of goodwill	(39,713)								0	(39,713)	0
Impairment of indefinite-lived intangibles									0	(4,549)	0
Capital Expenditures									70,020	101,425	70,372
Depreciation and amortization									94,082	87,344	63,348
Property, plant, and equipment, net	497,056				480,014				497,056	480,014
Energy Systems
Segment Reporting Information [Line Items]
Net sales									1,380,278	1,357,475	1,086,279
Operating earnings									67,060	67,809	45,164
Inventory step up to fair value relating to acquisitions									0	(304)	(7,789)
Restructuring and other exit charges									(3,187)	(7,284)	(10,593)
Legal proceedings charge, net									0	0	(4,363)
Capital Expenditures									34,826	40,768	24,333
Depreciation and amortization									57,864	53,793	32,052
Property, plant, and equipment, net	224,513				182,122				224,513	182,122
Energy Systems | Fixed Asset Write-Off
Segment Reporting Information [Line Items]
Restructuring and other exit charges									0	(50)	0
Motive Power
Segment Reporting Information [Line Items]
Net sales									1,163,710	1,348,193	1,391,844
Operating earnings									143,541	146,814	172,749
Restructuring and other exit charges									(36,798)	(2,021)	(5,751)
Legal proceedings charge, net									0	0	(74)
Capital Expenditures									14,154	22,285	26,112
Depreciation and amortization									21,706	20,900	20,725
Property, plant, and equipment, net	152,468				153,438				152,468	153,438
Motive Power | Fixed Asset Write-Off
Segment Reporting Information [Line Items]
Restructuring and other exit charges									0	(5,380)	0
Specialty
Segment Reporting Information [Line Items]
Net sales									433,944	382,200	329,894
Operating earnings									46,148	42,454	44,077
Inventory step up to fair value relating to acquisitions									0	(1,550)	(2,590)
Restructuring and other exit charges									(389)	(6,020)	(18,365)
Capital Expenditures									21,040	38,372	19,927
Depreciation and amortization									14,512	12,651	10,571
Property, plant, and equipment, net	$ 120,075				$ 144,454				120,075	144,454
Specialty | Fixed Asset Write-Off
Segment Reporting Information [Line Items]
Restructuring and other exit charges									$ 0	$ (11)	$ 0

Quarterly Financial Data (Detai

Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2021	Jan. 03, 2021	Oct. 04, 2020	Jul. 05, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 813,539	$ 751,067	$ 708,402	$ 704,924	$ 781,803	$ 763,698	$ 762,137	$ 780,230	$ 2,977,932	$ 3,087,868	$ 2,808,017
Gross profit	197,301	189,312	177,560	174,977	200,796	185,241	197,317	201,512	739,150	784,866	693,026
Operating earnings	51,669	56,071	55,415	53,220	20,065	43,084	58,710	68,336	216,375	190,195	212,465
Net earnings	33,836	38,624	35,731	35,183	(1,523)	27,305	62,698	48,636	143,374	137,116	160,627
Net earnings attributable to EnerSys stockholders	$ 33,836	$ 38,624	$ 35,731	$ 35,183	$ (1,523)	$ 27,305	$ 62,698	$ 48,636	$ 143,374	$ 137,116	$ 160,239
Basic earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.79	$ 0.91	$ 0.84	$ 0.83	$ (0.04)	$ 0.65	$ 1.48	$ 1.14	$ 3.37	$ 3.23	$ 3.79
Diluted earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.78	$ 0.89	$ 0.83	$ 0.82	$ (0.04)	$ 0.64	$ 1.47	$ 1.13	$ 3.32	$ 3.20	$ 3.73

Quarterly Financial Data (Addit

Quarterly Financial Data (Additional Information) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended			24 Months Ended
	Mar. 31, 2021	Jan. 03, 2021	Oct. 04, 2020	Jul. 05, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2021
Condensed Financial Statements, Captions [Line Items]
Gain on sale of certain licenses and assets		$ 4,397
Restructuring and other exit charges	$ 20,672	15,196	$ 3,119	$ 1,387	$ 2,695	$ 9,417	$ 6,282	$ 2,372	$ 40,374	$ 20,766	$ 34,709
Swiss tax reform, tax benefit				1,883
Inventory Write-down					(1,991)			$ 3,845
Impairment of goodwill	39,713								0	39,713	0
Impairment of indefinite-lived intangible assets	$ 4,549
Impact of Tax Act						$ 21,000			0	0	$ (13,483)
Richmond Kentucky Battery Formation Area Fire
Condensed Financial Statements, Captions [Line Items]
Restructuring charges, cash charges related to employee severance and other charges									7,500	$ 5,000
Gain on sale of certain licenses and assets									4,397
Restructuring and other exit charges					$ 5							$ 46,117
Business Interruption Claim | Richmond Kentucky Battery Formation Area Fire
Condensed Financial Statements, Captions [Line Items]
Restructuring charges, cash charges related to employee severance and other charges		$ 2,344	$ 1,456	$ 3,700					$ 12,500

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail)	May 20, 2021$ / shares
Subsequent Event | Dividend Declared
Subsequent Event [Line Items]
Common Stock cash dividends, per share	$ 0.175