Investment in Unconsolidated Ventures Investment in Unconsolidated Ventures (Summary of Results of Operations of Unconsolidated Ventures) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Schedule of Equity Method Investments [Line Items]
Company's share of income (Company's basis)	$ 1,535	$ 44
Unconsolidated Real Estate Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Revenue	40,889	38,593
Operating expenses	18,266	16,815
Interest expense, net	9,772	11,249
Depreciation and amortization	12,906	11,471
Net loss	(55)	(942)
Company's share of income (Company's basis)	$ 1,535	$ 44