CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Net income	$ 111,821	$ 101,984	$ 275,649	$ 170,764	$ 363,261
Other comprehensive income (loss):
Foreign currency translation	2,838	(7,293)	3,180	(4,234)
Change in unrealized gain on marketable debt securities	(509)	(1,285)	(1,220)	(2,964)
Other	(107)	(397)	(396)	(433)
Total other comprehensive income (loss)	2,222	(8,975)	1,564	(7,631)	(4,806)
Comprehensive income	114,043	93,009	277,213	163,133
Comprehensive loss attributable to noncontrolling interest	(61)	(901)	(884)	(781)
Comprehensive income attributable to common stockholders	$ 114,104	$ 93,910	$ 278,097	$ 163,914