Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 51,517	$ 29,432	$ 119,930	$ 79,463
Other comprehensive income (loss):
Foreign currency translation adjustments	2,357	302	5,453	(33,628)
Change in unrealized gains (losses) on available-for-sale securities, net of tax of $(412), $(45), $810 and $113, respectively	(676)	(72)	1,325	184
Total other comprehensive income (loss)	1,681	230	6,778	(33,444)
Comprehensive income	$ 53,198	$ 29,662	$ 126,708	$ 46,019