Investments in Real Estate Partnerships - Income Statment Summarized Financial Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of Equity Method Investments [Line Items]
Total revenues		$ 399,091	$ 437,029	$ 434,050
Depreciation and amortization		134,236	155,146	160,484
Operating and maintenance		62,442	67,541	63,855
General and administrative		7,905	7,383	8,247
Real estate taxes		49,103	55,926	59,339
Provision for doubtful accounts		3,160	2,951	10,062
Other expenses		317	715	2,098
Total operating expenses		257,163	289,662	304,085
Interest expense, net		112,099	129,581	137,794
Gain on sale of real estate		(7,464)	(8,976)	(6,141)
Gain on extinguishment of debt		(8,743)	0	0
Provision for impairment		0	78,908	104,416
Other expense (income)	2,600	776	(383)	72
Total other expense		96,668	199,130	236,141
Net income (loss)		45,260	(51,763)	(106,176)
Income (Loss) from Equity Method Investments		$ 9,643	$ (12,884)	$ (26,373)
Equity Method Investment - Other Income (Expense)		1.00%