Investments in Joint Ventures (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Condensed combined statements of operations
Total Revenues	$ 79,677	$ 78,586	$ 79,386	$ 80,186	$ 80,127	$ 78,186	$ 80,756	$ 82,709	$ 317,835	$ 321,778	$ 384,572
Expenses:
Interest									100,127	105,898	114,768
Depreciation and Amortization									121,604	125,298	131,871
Impairment of Real Estate					2,387				(8,807)	112,904	5,617
Gain on Sale of Real Estate	0	918	0	0		(214)		731	918	517	231
Net (Loss) Income									(9,190)	(221,619)	4,186
Company's Share of Net Income (Loss)	79	(3,990)	196	(3,730)	(22,974)	(149,385)	(13,548)	(16,914)	(7,445)	(202,821)	5,733
Equity in Income (Loss) of Joint Ventures	73	772	99	36	950	(398)	582	(459)	980	675	(6,470)
Corporate Joint Venture [Member]
Condensed combined statements of operations
Total Revenues									16,799	55,894	85,426
Expenses:
Operating and Other									3,114	23,862	41,359
Interest									7,791	28,622	39,749
Depreciation and Amortization									7,312	27,202	47,487
Impairment of Real Estate										3,268	150,804
Expenses									18,217	82,954	279,399
Income from Discontinued Operations (Including Gain on Sale of Real Estate of $3,137, $2,761 and $1,177 for the years ended December 31, 2011, 2010 and 2009, respectively)									2,674	1,942	1,799
Gain on Sale of Real Estate										808	8,603
Net (Loss) Income									1,256	(24,310)	(183,571)
Company's Share of Net Income (Loss)									980	675	(1,276)
Impairment on the Company Investments in Joint Ventures											(5,194)
Equity in Income (Loss) of Joint Ventures									$ 980	$ 675	$ (6,470)