CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 22,221	$ 16,288	$ 63,082	$ 55,412
Other comprehensive income (loss):
Foreign currency translation adjustments	82	34	(168)	585
Unrealized gains (losses) on cash flow hedges:
Unrealized cash flow hedge gains (losses) arising during the period	2,090	1,330	2,394	(3,484)
Net (gains) losses reclassified into income for revenue hedges	(2,178)	(1,739)	(3,163)	(7,474)
Net (gains) losses reclassified into income for cost of revenue hedges	756	1,238	2,072	3,182
Net unrealized gains (losses) on cash flow hedges	668	829	1,303	(7,776)
Unrealized holding gains (losses) during the period	(628)	(637)	(586)	(845)
Aggregate income tax benefit of the above items	156	150	130	348
Other comprehensive income (loss)	278	376	679	(7,688)
Comprehensive income	$ 22,499	$ 16,664	$ 63,761	$ 47,724