CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 82,599	$ 68,392	$ 112,301
Other comprehensive income (loss):
Foreign currency translation adjustments	(311)	376	476
Unrealized gains (losses) on cash flow hedges:
Unrealized cash flow hedge gains (losses) arising during the year	3,095	(3,786)	10,348
Net (gains) losses reclassified into net revenues for revenue hedges (effective portion)	(4,111)	(7,826)	(3,650)
Net (gains) losses reclassified into cost of revenues for cost of revenues hedges (effective portion)	2,663	4,801	449
Net unrealized gains (losses) on cash flow hedges	1,647	(6,811)	7,147
Unrealized holding gains (losses) during the year	(516)	(67)	2
Aggregate income tax benefit (expense) of the above items	115	141	(143)
Other comprehensive income (loss)	935	(6,361)	7,482
Comprehensive income	$ 83,534	$ 62,031	$ 119,783