Earnings Per Share - Reconciliation from Basic to Diluted Average Common Shares (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 02, 2016	Sep. 27, 2015	Oct. 02, 2016	Sep. 27, 2015
Earnings Per Share [Abstract]
Net earnings attributable to EnerSys stockholders	$ 45,636	$ 40,025	$ 90,209	$ 88,412
Basic	43,426,955	44,944,027	43,348,449	44,588,971
Common shares from exercise and lapse of equity awards, net of shares assumed reacquired	522,588	666,875	541,229	685,154
3.375% Convertible Notes due 2038	0	394,497	0	1,106,762
Diluted weighted-average number of common shares outstanding	43,949,543	46,005,399	43,889,678	46,380,887
Basic earnings per common share attributable to EnerSys stockholders (in dollars per share)	$ 1.05	$ 0.89	$ 2.08	$ 1.98
Diluted earnings per common share attributable to EnerSys stockholders (in dollars per share)	$ 1.04	$ 0.87	$ 2.06	$ 1.91
Anti-dilutive equity awards not included in diluted weighted-average common shares	245,199	742	317,578	742