Risk Management and Use of Derivative Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Derivatives, Fair Value
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	$ 5,127	$ 3,780
Liability Derivatives Fair Value at	(29,470)	(21,812)
Interest rate cap | Designated as Hedging Instrument | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	29	2
Stock warrants | Not Designated as Hedging Instrument | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	3,619	2,160
Foreign currency contracts | Designated as Hedging Instrument | Accounts Payable and Accrued Liabilities
Derivatives, Fair Value
Liability Derivatives Fair Value at	(12,893)	(7,083)
Interest rate swap | Designated as Hedging Instrument | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	1,479	1,618
Interest rate swap | Designated as Hedging Instrument | Accounts Payable and Accrued Liabilities
Derivatives, Fair Value
Liability Derivatives Fair Value at	(5,216)	(2,734)
Interest rate swap | Not Designated as Hedging Instrument | Accounts Payable and Accrued Liabilities
Derivatives, Fair Value
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	0	0
Liability Derivatives Fair Value at	$ (11,361)	$ (11,995)