CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 112,301	$ 112,417	$ 106,402
Other comprehensive income:
Foreign currency translation adjustments	476	(244)	(261)
Unrealized gains (losses) on cash flow hedges:
Unrealized cash flow hedge gains (losses) arising during the year	10,348	(3,750)	3,441
Net (gains) losses reclassified into net revenues for revenue hedges (effective portion)	(3,650)	965	(3,367)
Net (gains) losses reclassified into cost of revenues for cost of revenues hedges (effective portion)	449	(28)	(640)
Net unrealized gains (losses) on cash flow hedges	7,147	(2,813)	(566)
Unrealized holding gains during the year	2	101	35
Aggregate income tax benefit (expense) of the above items	(143)	27	2
Other comprehensive income (loss)	7,482	(2,929)	(790)
Comprehensive income	$ 119,783	$ 109,488	$ 105,612