Summary Financial Information (OCI Statement) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Net income	$ 22,065	$ 8,984	$ 19,579
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	21,717	(9,379)	3,650
Change in derivatives qualifying as hedges, net of tax	3,563	(3,514)	(1,031)
Change in investments:
Unrealized holdings gain arising during the period	189	173	(79)
Reclassification adjustment for gain included in net income, net of tax	0	(105)	(154)
Net change in unrealized gain (loss) on investments	189	68	(233)
Total other comprehensive income (loss)	38,206	(2,717)	(2,299)
Comprehensive income	$ 60,271	$ 6,267	$ 17,280