CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 28,672	$ 26,953
Other comprehensive income (loss):
Foreign currency translation adjustments	63	(352)
Unrealized gains (losses) on cash flow hedges:
Unrealized cash flow hedge gains (losses) arising during the period	73	(1,663)
Net losses reclassified into income for revenue hedges	870	16
Net gains reclassified into income for cost of revenue hedges	(108)	(270)
Net unrealized gains (losses) on cash flow hedges	835	(1,917)
Unrealized holding gains (losses) during the period	77	(214)
Aggregate income tax benefit (expense) of the above items	(36)	97
Other comprehensive (income) loss	939	(2,386)
Comprehensive income	$ 29,611	$ 24,567