Risk Management and Use of Derivative Financial Instruments (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Amount of Gain (Loss) Recognized in Income on Derivatives
Amount of Gain (Loss) Recognized in Income on Derivatives	$ 478	$ 1,959
Interest rate swap | Interest expense
Amount of Gain (Loss) Recognized in Income on Derivatives
Amount of Gain (Loss) Recognized in Income on Derivatives	478	1,679
Stock warrants | Other income and (expenses)
Amount of Gain (Loss) Recognized in Income on Derivatives
Amount of Gain (Loss) Recognized in Income on Derivatives	$ 0	$ 280