Risk Management and Use of Derivative Financial Instruments (Details 3) - Derivatives in Cash Flow Hedging Relationships - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Amount of Gain (Loss) on Derivatives Reclassified from Other Comprehensive Income (Loss) into Income (Effective Portion)
Amount of Gain (Loss) on Derivatives Reclassified from Other Comprehensive Income (Loss) into Income (Effective Portion)	$ 160	$ (44)
Foreign currency forward contracts and collars | Other income and (expenses)
Amount of Gain (Loss) on Derivatives Reclassified from Other Comprehensive Income (Loss) into Income (Effective Portion)
Amount of Gain (Loss) on Derivatives Reclassified from Other Comprehensive Income (Loss) into Income (Effective Portion)	372	256
Interest rate swaps | Interest expense
Amount of Gain (Loss) on Derivatives Reclassified from Other Comprehensive Income (Loss) into Income (Effective Portion)
Amount of Gain (Loss) on Derivatives Reclassified from Other Comprehensive Income (Loss) into Income (Effective Portion)	$ (212)	$ (300)