CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 18,883	$ 22,829	$ 40,440	$ 47,682
Other comprehensive income (loss):
Change in foreign currency translation adjustment, net of tax benefit (expense) of $(248), $(118), $1,312 and $(279)	6,952	(312)	(10,051)	257
Available-for-sale investments:
Change in net unrealized gain, net of tax expense of $(43), $(77), $(198) and $(134)	68	125	319	218
Less: reclassification adjustment for net gain included in net income, net of tax expense of $(118), $(1), $(120) and $(2)	(189)	(2)	(192)	(4)
Net change, net of tax (expense) benefit of $75, $(76), $(78) and $(132)	(121)	123	127	214
Cash flow hedges:
Change in unrealized (loss) gain, net of tax benefit (expense) of $72, $(250), $(404) and $(800)	(117)	406	654	1,304
Less: reclassification adjustment for net (gain) loss included in net income, net of tax (expense) benefit of $(23), $(104), $(160) and $81	(36)	(168)	(257)	133
Net change, net of tax (expense) benefit of $95, $(146), $(244) and $(881)	(153)	238	397	1,437
Total other comprehensive income (loss), net of tax effect	6,678	49	(9,527)	1,908
Total comprehensive income, net of tax effect	$ 25,561	$ 22,878	$ 30,913	$ 49,590