Stockholder's Equity (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Summary of comprehensive income/(loss)
Unrecognized gain (losses) on cash flow hedges	$ 414		$ 191		$ 1,138		$ 1,059
Unrecognized gains (losses) on equity investments	230		(400)		192		(314)
Unrecognized gain (loss) on foreign currency translation	2,514		0		166		0
Total other comprehensive income (loss)	3,158		(209)		1,496		745
Net income attributable to controlling interests	53,871		53,841		190,077		173,094
Comprehensive income (loss) attributable to controlling interests	57,029		53,632		191,573		173,839
Less: Net income (loss) attributable to noncontrolling interests	(365)	[1]	(1,488)	[1]	(2,241)	[1]	(2,721)	[1]
Total comprehensive income (loss) attributable to stockholders	$ 56,664		$ 52,144		$ 189,332		$ 171,118

[1] Includes amounts attributable to redeemable noncontrolling interests.