Investment in Unconsolidated Ventures (Summary of Results of Operations of Unconsolidated Real Estate Ventures) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Summary of results of operations of Real Estate Ventures
Company's share of income (Company's basis)	$ 500,000	$ 418,000	$ 1,382,000	$ 2,739,000
Loss on real estate venture formation	(950,000)	0	(950,000)	0
Unconsolidated real estate ventures [Member]
Summary of results of operations of Real Estate Ventures
Revenue	42,772,000	36,345,000	120,644,000	108,743,000
Operating expenses	18,753,000	15,863,000	51,819,000	46,407,000
Interest expense, net	10,233,000	10,326,000	31,100,000	31,999,000
Depreciation and amortization	12,947,000	9,869,000	36,067,000	28,836,000
Net income	839,000	287,000	1,658,000	1,501,000
Guaranteed repayment of loans on behalf of a certain Real Estate Venture	$ 600,000		$ 600,000