Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 509	$ 617	$ 888
Charged to costs and expenses	1,063	648	942
Deductions	(672)	(756)	(1,213)
Balance at end of year	900	509	617
Deferred Tax Valuation Allowance [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	80,013	77,846	76,420
Charged to costs and expenses	(25,753)	2,167	1,426
Deductions	0	0	0
Balance at end of year	$ 54,260	$ 80,013	$ 77,846