Fair Value Measurements (Details) (Fair value measurement, recurring basis [Member], USD $)	Sep. 30, 2014		Dec. 31, 2013
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Fair value adjustment to the borrowings subject to TRS	$ 6,590,000		$ 8,869,000
Redeemable noncontrolling interest	(186,834,000)	[1]	(171,743,000)
Fair value of financial assets and liabilities and redeemable noncontrolling interests on a recurring basis	(280,826,000)		(284,923,000)
Interest rate caps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	258,000		155,000
Interest rate swaps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative liabilities	(79,406,000)		(97,858,000)
Total Return Swap [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	5,849,000		903,000
Derivative liabilities	(27,283,000)		(25,249,000)
Fair Value, Inputs, Level 1 [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Fair value adjustment to the borrowings subject to TRS	0		0
Redeemable noncontrolling interest	0		0
Fair value of financial assets and liabilities and redeemable noncontrolling interests on a recurring basis	0		0
Fair Value, Inputs, Level 1 [Member] | Interest rate caps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	0		0
Fair Value, Inputs, Level 1 [Member] | Interest rate swaps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative liabilities	0		0
Fair Value, Inputs, Level 1 [Member] | Total Return Swap [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Inputs, Level 2 [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Fair value adjustment to the borrowings subject to TRS	0		0
Redeemable noncontrolling interest	0		0
Fair value of financial assets and liabilities and redeemable noncontrolling interests on a recurring basis	(855,000)		(343,000)
Fair Value, Inputs, Level 2 [Member] | Interest rate caps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	258,000		155,000
Fair Value, Inputs, Level 2 [Member] | Interest rate swaps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative liabilities	(1,113,000)		(498,000)
Fair Value, Inputs, Level 2 [Member] | Total Return Swap [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Inputs, Level 3 [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Fair value adjustment to the borrowings subject to TRS	6,590,000		8,869,000
Redeemable noncontrolling interest	(186,834,000)	[1]	(171,743,000)
Fair value of financial assets and liabilities and redeemable noncontrolling interests on a recurring basis	(279,971,000)		(284,580,000)
Fair Value, Inputs, Level 3 [Member] | Interest rate caps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	0		0
Fair Value, Inputs, Level 3 [Member] | Interest rate swaps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative liabilities	(78,293,000)		(97,360,000)
Fair Value, Inputs, Level 3 [Member] | Total Return Swap [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	5,849,000		903,000
Derivative liabilities	$ (27,283,000)		$ (25,249,000)

[1] As of September 30, 2014, the redeemable noncontrolling interest is recorded at book value.