Risk Management and Use of Derivative Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Derivatives, Fair Value
Asset Derivatives Fair Value at	$ 4,303	$ 3,780
Liability Derivatives Fair Value at	(29,134)	(21,812)
Interest rate caps | Designated as Hedging Instrument | Other Assets
Derivatives, Fair Value
Asset Derivatives Fair Value at	12	2
Stock warrants | Not Designated as Hedging Instrument | Other Assets
Derivatives, Fair Value
Asset Derivatives Fair Value at	3,485	2,160
Foreign currency contracts | Designated as Hedging Instrument | Accounts Payable and Accrued Liabilities
Derivatives, Fair Value
Liability Derivatives Fair Value at	(12,506)	(7,083)
Interest rate swap | Designated as Hedging Instrument | Other Assets
Derivatives, Fair Value
Asset Derivatives Fair Value at	806	1,618
Interest rate swap | Designated as Hedging Instrument | Accounts Payable and Accrued Liabilities
Derivatives, Fair Value
Liability Derivatives Fair Value at	(5,894)	(2,734)
Interest rate swap | Not Designated as Hedging Instrument | Accounts Payable and Accrued Liabilities
Derivatives, Fair Value
Liability Derivatives Fair Value at	$ (10,734)	$ (11,995)