Fair Value Measurements (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Fair value adjustment to the borrowings subject to TROR	$ 5,099,700,000		$ 5,346,196,000
Fair value measurement, recurring basis [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Fair value adjustment to the borrowings subject to TROR	4,196,000		5,604,000
Redeemable noncontrolling interest	(178,050,000)	[1]	(183,038,000)	[1]
Total fair value	(260,868,000)		(271,434,000)
Fair value measurement, recurring basis [Member] | Interest rate caps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	27,000		126,000
Fair value measurement, recurring basis [Member] | Interest rate swaps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative liabilities	(72,331,000)		(75,281,000)
Fair value measurement, recurring basis [Member] | TROR [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	12,167,000		8,236,000
Derivative liabilities	(26,877,000)		(27,081,000)
Fair Value, Inputs, Level 1 [Member] | Fair value measurement, recurring basis [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Fair value adjustment to the borrowings subject to TROR	0		0
Redeemable noncontrolling interest	0		0
Total fair value	0		0
Fair Value, Inputs, Level 1 [Member] | Fair value measurement, recurring basis [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] | Fair value measurement, recurring basis [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] | Fair value measurement, recurring basis [Member] | TROR [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] | Fair value measurement, recurring basis [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Fair value adjustment to the borrowings subject to TROR	0		0
Redeemable noncontrolling interest	0		0
Total fair value	(2,289,000)		(1,619,000)
Fair Value, Inputs, Level 2 [Member] | Fair value measurement, recurring basis [Member] | Interest rate caps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	27,000		126,000
Fair Value, Inputs, Level 2 [Member] | Fair value measurement, recurring basis [Member] | Interest rate swaps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative liabilities	(2,316,000)		(1,745,000)
Fair Value, Inputs, Level 2 [Member] | Fair value measurement, recurring basis [Member] | TROR [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] | Fair value measurement, recurring basis [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Fair value adjustment to the borrowings subject to TROR	4,196,000		5,604,000
Redeemable noncontrolling interest	(178,050,000)	[1]	(183,038,000)	[1]
Total fair value	(258,579,000)		(269,815,000)
Fair Value, Inputs, Level 3 [Member] | Fair value measurement, recurring basis [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] | Fair value measurement, recurring basis [Member] | Interest rate swaps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative liabilities	(70,015,000)		(73,536,000)
Fair Value, Inputs, Level 3 [Member] | Fair value measurement, recurring basis [Member] | TROR [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	12,167,000		8,236,000
Derivative liabilities	$ (26,877,000)		$ (27,081,000)

[1] Redeemable noncontrolling interest is recorded at historical cost for period presented.