Business Segments - (Goodwill) (Details) $ in Thousands	6 Months Ended
	Oct. 04, 2020 USD ($)
Segment Reporting Information [Line Items]
Balance at March 31, 2020	$ 663,936
Measurement period adjustments	2,996
Foreign currency translation adjustment	22,116
Balance as of October 4, 2020	689,048
Energy Systems
Segment Reporting Information [Line Items]
Balance at March 31, 2020	263,150
Measurement period adjustments	1,348
Foreign currency translation adjustment	8,334
Balance as of October 4, 2020	272,832
Motive Power
Segment Reporting Information [Line Items]
Balance at March 31, 2020	308,497
Measurement period adjustments	0
Foreign currency translation adjustment	11,076
Balance as of October 4, 2020	319,573
Specialty
Segment Reporting Information [Line Items]
Balance at March 31, 2020	92,289
Measurement period adjustments	1,648
Foreign currency translation adjustment	2,706
Balance as of October 4, 2020	$ 96,643