Summary Financial Information (OCI Statement) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Net income	$ 59,672	$ 42,577	$ 22,065
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(9,004)	(16,708)	21,717
Change in derivatives qualifying as hedges, net of tax	1,602	(1,037)	3,563
Change in investments:
Unrealized holdings gain arising during the period	0	0	189
Net change in unrealized gain (loss) on investments	0	0	189
Total other comprehensive income (loss)	(31,298)	(22,912)	38,206
Comprehensive income	$ 28,374	$ 19,665	$ 60,271