Stockholder's Equity (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Summary of comprehensive income/(loss)
Unrecognized gain (losses) on cash flow hedges	$ 446		$ 386		$ 724		$ 868
Unrecognized gains (losses) on equity investments	(46)		(236)		(38)		86
Unrecognized gain (loss) on foreign currency translation	(2,348)		0		(2,348)		0
Total other comprehensive income (loss)	(1,948)		150		(1,662)		954
Net income attributable to controlling interests	77,696		87,200		136,205		119,252
Comprehensive income (loss) attributable to controlling interests	75,748		87,350		134,543		120,206
Less: Net income (loss) attributable to noncontrolling interests	(821)	[1]	(992)	[1]	(1,876)	[1]	(1,234)	[1]
Total comprehensive income (loss) attributable to stockholders	$ 74,927		$ 86,358		$ 132,667		$ 118,972

[1] Includes amounts attributable to redeemable noncontrolling interests.