CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 23,117	$ 109,654	$ 294,162	$ 369,404	$ 477,186
Other comprehensive loss:
Foreign currency translation	(11,239)	(12,885)	(7,718)	(7,906)
Change in unrealized gain on marketable securities	0	(334)	(5,046)	1,237
Other	467	3,120	(949)	3,166
Total other comprehensive loss	(10,772)	(10,099)	(13,713)	(3,503)	$ (6,538)
Comprehensive income	12,345	99,555	280,449	365,901
Comprehensive income attributable to noncontrolling interest	265	522	1,047	827
Comprehensive income attributable to common stockholders	$ 12,080	$ 99,033	$ 279,402	$ 365,074