Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Deferred Tax Valuation Allowance [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	$ 57,852	$ 54,260	$ 80,013
Charged to costs and expenses	8,967	3,592	(25,753)
Balance at end of year	66,819	57,852	54,260
Allowance for Doubtful Accounts [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	788	900	509
Charged to costs and expenses	1,434	539	1,063
Deductions	(588)	(651)	(672)
Balance at end of year	$ 1,634	$ 788	$ 900