Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 781,803	$ 763,698	$ 762,137	$ 780,230	$ 796,603	$ 680,022	$ 660,462	$ 670,930	$ 3,087,868	$ 2,808,017	$ 2,581,891
Gross profit	200,796	185,241	197,317	201,512	202,266	164,546	160,880	165,334	784,866	693,026	658,404
Operating earnings	20,065	43,084	58,710	68,336	34,978	49,951	63,357	64,179	190,195	212,465	270,846
Net earnings	(1,523)	27,305	62,698	48,636	18,546	48,614	47,447	46,020	137,116	160,627	119,833
Net earnings attributable to EnerSys stockholders	$ (1,523)	$ 27,305	$ 62,698	$ 48,636	$ 18,538	$ 48,417	$ 47,424	$ 45,860	$ 137,116	$ 160,239	$ 119,594
Basic earnings per common share attributable to EnerSys stockholders (usd per share)	$ (0.04)	$ 0.65	$ 1.48	$ 1.14	$ 0.43	$ 1.14	$ 1.13	$ 1.09	$ 3.23	$ 3.79	$ 2.81
Diluted earnings per common share attributable to EnerSys stockholders (usd per share)	$ (0.04)	$ 0.64	$ 1.47	$ 1.13	$ 0.42	$ 1.12	$ 1.11	$ 1.08	$ 3.20	$ 3.73	$ 2.77