Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 31,822	$ 7,675	$ 63,982	$ 9,255
Other comprehensive income (loss):
Foreign currency translation adjustments	2,409	1,084	150	1,128
Change in unrealized gains (losses) on available-for-sale securities, net of tax of $515, $604, $(936), and $736, respectively	825	961	(1,499)	1,172
Total other comprehensive income (loss)	3,234	2,045	(1,349)	2,300
Comprehensive income	$ 35,056	$ 9,720	$ 62,633	$ 11,555