Restructuring - Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Reconciliation of restructuring liability
Costs charged to expense (1)	$ 8,882	$ 8,779	$ 14,843
Personnel reduction costs
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment			0
Reconciliation of restructuring liability
Balance at the beginning of the period	1,865	9,629	999
Costs charged to expense (1)	7,618	2,823	12,587
Costs paid or settled	(7,976)	(10,329)	(3,901)
Change in foreign exchange	3	(258)	147
Balance at the end of the period	1,510	1,865	9,629
Personnel reduction costs
Reconciliation of restructuring liability
Costs charged to expense (1)			12,384
Manufacturing and sales office relocation costs
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment			312
Reconciliation of restructuring liability
Balance at the beginning of the period	316	330	406
Costs charged to expense (1)	1,264	5,956	2,256
Costs paid or settled	(1,264)	(5,957)	(2,662)
Change in foreign exchange	7	(13)	18
Balance at the end of the period	323	316	330
Employee Relocation
Reconciliation of restructuring liability
Costs charged to expense (1)			200
Film and Electrolytic
Reconciliation of restructuring liability
Costs charged to expense (1)	3,458	2,717	$ 5,788
Film and Electrolytic | Personnel reduction costs
Reconciliation of restructuring liability
Costs charged to expense (1)	$ 500	$ 300