Risk Management and Use of Derivative Financial Instruments (Details 4) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Amount of Gain (Loss) on Derivatives Recognized in Income
Amount of gain (loss) recognized income on derivatives	$ 459	$ (78)	$ 519	$ (209)
Embedded derivatives | Not designated | Other income and (expense)
Amount of Gain (Loss) on Derivatives Recognized in Income
Amount of gain (loss) recognized income on derivatives	25	163	262	281
Stock warrants | Not designated | Other income and (expense)
Amount of Gain (Loss) on Derivatives Recognized in Income
Amount of gain (loss) recognized income on derivatives	231	(66)	66	(66)
Swaption | Not designated | Other income and (expense)
Amount of Gain (Loss) on Derivatives Recognized in Income
Amount of gain (loss) recognized income on derivatives	127	(172)	35	(430)
Foreign currency forward | Not designated | Other income and (expense)
Amount of Gain (Loss) on Derivatives Recognized in Income
Amount of gain (loss) recognized income on derivatives	(12)	(56)	(16)	(118)
Interest rate swap | Designated as hedging | Interest expense
Amount of Gain (Loss) on Derivatives Recognized in Income
Amount of gain (loss) recognized income on derivatives	$ 88	$ 53	$ 172	$ 124