Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 59,295	$ 31,822	$ 183,428	$ 63,982
Other comprehensive income (loss):
Foreign currency translation adjustments	(4,354)	2,409	(1,975)	150
Change in unrealized gains (losses) on available-for-sale securities, net of tax of $(313), $515, $28, and $(936), respectively	(503)	825	45	(1,499)
Total other comprehensive income (loss)	(4,857)	3,234	(1,930)	(1,349)
Comprehensive income	$ 54,438	$ 35,056	$ 181,498	$ 62,633