v3.7.0.1

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, 2017	Jan. 01, 2017	Oct. 02, 2016	Jul. 03, 2016	Mar. 31, 2016	Dec. 27, 2015	Sep. 27, 2015	Jun. 28, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share [Abstract]
Net earnings attributable to EnerSys stockholders	$ 33,770	$ 36,235	$ 45,636	$ 44,573	$ 9,260	$ 38,478	$ 40,025	$ 48,387	$ 160,214	$ 136,150	$ 181,188
Basic (in shares)									43,389,333	44,276,713	45,606,317
Dilutive effect of:
Common shares from exercise and lapse of equity awards, net of shares assumed reacquired (in shares)									623,210	644,036	879,406
Convertible Notes (in shares)									0	553,381	1,567,006
Diluted weighted-average number of common shares outstanding (in shares)									44,012,543	45,474,130	48,052,729
Basic earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.78	$ 0.83	$ 1.05	$ 1.03	$ 0.21	$ 0.87	$ 0.89	$ 1.09	$ 3.69	$ 3.08	$ 3.97
Diluted earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.76	$ 0.82	$ 1.04	$ 1.02	$ 0.21	$ 0.86	$ 0.87	$ 1.03	$ 3.64	$ 2.99	$ 3.77
Anti-dilutive equity awards not included in diluted weighted-average common shares (in shares)									1,295,000	0	0

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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