CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 20,474	$ 17,896	$ 40,861	$ 39,124
Other comprehensive income (loss):
Foreign currency translation adjustments	4	563	(250)	551
Unrealized gains (losses) on cash flow hedges:
Unrealized cash flow hedge gains (losses) arising during the period	(650)	(1,976)	304	(4,814)
Net (gains) losses reclassified into income for revenue hedges	825	2,197	985	5,735
Net (gains) losses reclassified into income for cost of revenue hedges	589	1,171	1,316	1,944
Net unrealized gains (losses) on cash flow hedges	(886)	(3,002)	635	(8,605)
Unrealized holding gains (losses) during the period	(272)	(126)	42	(208)
Aggregate income tax benefit (expense) of the above items	98	66	(26)	198
Other comprehensive income (loss)	(1,056)	(2,499)	401	(8,064)
Comprehensive income	$ 19,418	$ 15,397	$ 41,262	$ 31,060