Discontinued Operations (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
REVENUES
Rental income	$ 3,764,000	$ 75,310,000	$ 87,279,000	$ 213,221,000
Total revenues	3,764,000	75,310,000	87,279,000	213,221,000
EXPENSES
Property and maintenance	2,202,000	31,051,000	46,177,000	85,544,000
Real estate taxes and insurance	151,000	5,619,000	5,369,000	17,162,000
Depreciation	901,000	15,701,000	14,344,000	43,873,000
General and administrative	2,000	13,000	49,000	32,000
Total expenses	3,256,000	52,384,000	65,939,000	146,611,000
Discontinued operating income	508,000	22,926,000	21,340,000	66,610,000
Interest and other income	42,000	7,000	140,000	640,000
Interest:
Expense incurred, net	(21,000)	(2,056,000)	(83,000)	(6,032,000)
Amortization of deferred financing costs	0	(28,000)	(640,000)	(252,000)
Income and other tax (expense) benefit	93,000	(13,000)	31,000	(66,000)
Discontinued operations	622,000	20,836,000	20,788,000	60,900,000
Net (gain) on sales of discontinued operations	76,864,000	9,285,000	(759,100,000)	(69,538,000)
Discontinued operations, net	77,486,000	30,121,000	779,888,000	130,438,000
Discontinued Operations (Textuals) [Abstract]
Investment in real estate, net of accumulated depreciation	623,700,000		623,700,000
Mortgage notes payable					$ 50,900,000