CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 138,566	$ 114,533	$ 259,840	$ 227,631
Other comprehensive income (loss):
Foreign currency translation	2,761	(2,722)	(573)	(4,813)
Change in unrealized gain on intra-entity currency loan	4,958	0	5,552	0
Change in unrealized gain on marketable securities	265	(868)	1,571	(807)
Other	(193)	1,514	46	2,018
Total other comprehensive income (loss)	7,791	(2,076)	6,596	(3,602)
Comprehensive income	146,357	112,457	266,436	224,029
Comprehensive income (loss) attributable to noncontrolling interest	168	(47)	395	858
Comprehensive income attributable to common stockholders	$ 146,189	$ 112,504	$ 266,041	$ 223,171