CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 199,148	$ 149,034	$ 651,490
Other comprehensive income (loss):
Foreign currency translation	4,082	(10,668)
Change in unrealized gain on marketable securities	(123)	181
Other	(82)	(1,880)
Total other comprehensive income (loss)	3,877	(12,367)	$ (49,969)
Comprehensive income	203,025	136,667
Comprehensive income attributable to noncontrolling interests	1,021	54
Comprehensive income attributable to common stockholders	$ 202,004	$ 136,613