Risk Management and Use of Derivative Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Derivative assets, fair value, net	$ 7,334	$ 8,458
Derivative liability, fair value, net	(22,894)	(23,816)
Interest rate cap | Designated as hedging | Other assets
Derivatives, Fair Value [Line Items]
Derivative assets, fair value, net	0	1
Interest rate swap | Designated as hedging | Other assets
Derivatives, Fair Value [Line Items]
Derivative assets, fair value, net	962	0
Interest rate swap | Designated as hedging | Accounts payable, accrued expenses and other liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value, net	(14,288)	(20,142)
Stock warrants | Not designated | Other assets
Derivatives, Fair Value [Line Items]
Derivative assets, fair value, net	1,716	1,485
Foreign currency forward | Designated as hedging | Other assets
Derivatives, Fair Value [Line Items]
Derivative assets, fair value, net	1,524	4,229
Foreign currency forward | Designated as hedging | Accounts payable, accrued expenses and other liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value, net	(6,977)	(2,533)
Foreign currency forward | Not designated | Other assets
Derivatives, Fair Value [Line Items]
Derivative assets, fair value, net	1,076
Derivative liability, fair value, net		0
Foreign currency collars | Designated as hedging | Other assets
Derivatives, Fair Value [Line Items]
Derivative assets, fair value, net	1,041	2,743
Embedded derivatives | Not designated | Accounts payable, accrued expenses and other liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value, net	(1,629)	(1,141)
Swaption | Not designated | Other assets
Derivatives, Fair Value [Line Items]
Derivative assets, fair value, net	1,015
Derivative liability, fair value, net		$ 0