Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Deferred Tax Valuation Allowance [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	$ 66,819	$ 57,852	$ 54,260
Charged to costs and expenses	7,812	8,967	3,592
Balance at end of year	74,631	66,819	57,852
Allowance for Doubtful Accounts [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	1,634	788	900
Charged to costs and expenses	508	1,434	539
Deductions	922	(588)	(651)
Balance at end of year	$ 1,220	$ 1,634	$ 788