Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net income	$ 61,895	$ 44,239	$ 133,382	$ 87,466
Other comprehensive loss:
Foreign currency translation adjustments	(3,746)	(3,702)	(7,760)	(3,030)
Change in unrealized (loss) gain on investments, net of income tax benefit (expense) of $913, $62, $903 and $(113) for the three and six months ended June 30, 2013 and 2012, respectively	(1,626)	(99)	(1,555)	181
Other comprehensive loss	(5,372)	(3,801)	(9,315)	(2,849)
Comprehensive income	$ 56,523	$ 40,438	$ 124,067	$ 84,617