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	$ 651,490	$ 419,222	$ 477,001
Other comprehensive loss:
Foreign currency translation	(52,266)	(14,792)	(17,153)
Change in unrealized gain on marketable debt securities	(310)	(5,236)	7,001
Other	2,607	(658)	3,614
Total other comprehensive loss	(49,969)	(20,686)	(6,538)
Comprehensive income	601,521	398,536	470,463
Comprehensive income attributable to noncontrolling interest	2,259	1,379	1,234
Comprehensive income attributable to common stockholders	$ 599,262	$ 397,157	$ 469,229