Stockholders Equity and Noncontrolling Interests Reclassification from Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Mar. 31, 2017	Jan. 01, 2017	Oct. 02, 2016	Jul. 03, 2016	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Cost of goods sold									$ 1,921,494	$ 1,714,367	$ 1,704,472
Income tax expense									118,493	54,472	50,113
Net earnings attributable to EnerSys stockholders	$ (54,018)	$ 25,847	$ (43,222)	$ (48,201)	$ (33,770)	$ (36,235)	$ (45,636)	$ (44,573)	(119,594)	(160,214)	(136,150)
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									(3,142)	(6,236)	7,144
Income tax expense									610	2,300	(2,634)
Net earnings attributable to EnerSys stockholders									(2,532)	(3,936)	4,510
Pension funded status adjustment | Reclassification out of Accumulated Other Comprehensive Income
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Prior service costs and deferrals									1,771	1,431	2,043
Income tax expense									(411)	(466)	(483)
Net earnings attributable to EnerSys stockholders									$ 1,360	$ 965	$ 1,560