CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ (869)	$ 82,599	$ 68,392
Other comprehensive income (loss):
Foreign currency translation adjustments	257	(311)	376
Unrealized gains (losses) on cash flow hedges:
Unrealized cash flow hedge gains (losses) arising during the year	(6,741)	3,095	(3,786)
Net (gains) losses reclassified into net revenues for revenue hedges (effective portion)	4,715	(4,111)	(7,826)
Net (gains) losses reclassified into cost of revenues for cost of revenues hedges (effective portion)	(208)	2,663	4,801
Net unrealized gains (losses) on cash flow hedges	(2,234)	1,647	(6,811)
Unrealized holding gains (losses) during the year	48	(516)	(67)
Aggregate income tax benefit (expense) of the above items	105	115	141
Other comprehensive income (loss)	(1,824)	935	(6,361)
Comprehensive income (loss)	$ (2,693)	$ 83,534	$ 62,031