CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net Income	$ 129,535	$ 85,436	$ 67,560
Other comprehensive income (loss):
Unrealized gain on available-for-sale securities		1,488	22,977
Reclassification of unrealized gain to a realized gain on available-for-sale securities		(24,465)
Foreign currency translation adjustments	(22,524)	(28,716)	(19,545)
Total other comprehensive income (loss)	(22,524)	(51,693)	3,432
Comprehensive income	$ 107,011	$ 33,743	$ 70,992