Restructuring Costs (Cumulative Restructuring Costs) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Employee termination benefits		$ 2,625		$ 2,625
Other		1,766
Restructuring Charges		4,391
Property, plant and equipment		13,886
Inventory		1,702
Total impairment costs		15,588
Total restructuring and impairment costs	[1]	$ 19,979	$ 0	$ 19,979	$ 0

[1] Restructuring and impairment costs are excluded from segment operating income, but are included in consolidated operating income in the consolidated statements of income and comprehensive income. See Note 4 for additional information.