CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 121,274	$ 113,098
Foreign currency translation	(3,334)	(2,091)
Change in unrealized gain on intra-entity currency loan	594	0
Change in unrealized gain on marketable debt securities	1,306	61
Other	239	504
Total other comprehensive loss	(1,195)	(1,526)
Comprehensive income	120,079	111,572
Comprehensive income attributable to noncontrolling interest	227	905
Comprehensive income attributable to common stockholders	$ 119,852	$ 110,667