CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 109,701	$ 118,599	$ 369,541	$ 346,230	$ 454,889
Other comprehensive (loss) income:
Foreign currency translation	(2,747)	1,665	(3,320)	(3,148)
Change in unrealized gain on intra-entity currency loan	(10,138)	0	(4,586)	0
Change in unrealized gain on marketable securities	(334)	(208)	1,237	(1,015)
Other	3,120	84	3,166	2,102
Total other comprehensive (loss) income	(10,099)	1,541	(3,503)	(2,061)	(3,695)
Comprehensive income	99,602	120,140	366,038	344,169
Comprehensive income attributable to noncontrolling interest	569	303	964	1,161
Comprehensive income attributable to common stockholders	$ 99,033	$ 119,837	$ 365,074	$ 343,008