Discontinued Operations (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
REVENUES
Rental income	$ 24,065,000	$ 64,577,000	$ 70,787,000	$ 126,365,000
Total revenues	24,065,000	64,577,000	70,787,000	126,365,000
EXPENSES
Property and maintenance	17,950,000	26,071,000	40,690,000	51,349,000
Real estate taxes and insurance	989,000	4,943,000	3,859,000	10,149,000
Depreciation	2,480,000	12,245,000	9,749,000	24,712,000
General and administrative	36,000	14,000	47,000	19,000
Total expenses	21,455,000	43,273,000	54,345,000	86,229,000
Discontinued operating income	2,610,000	21,304,000	16,442,000	40,136,000
Interest and other income	92,000	626,000	97,000	632,000
Interest:
Expense incurred, net	(77,000)	(2,097,000)	204,000	(3,650,000)
Amortization of deferred financing costs	(530,000)	(19,000)	(594,000)	(221,000)
Income and other tax (expense) benefit	(19,000)	3,000	(61,000)	(52,000)
Discontinued operations	2,076,000	19,817,000	16,088,000	36,845,000
Net (gain) on sales of discontinued operations	558,482,000	217,000	(682,236,000)	(60,253,000)
Discontinued operations, net	560,558,000	20,034,000	698,324,000	97,098,000
Discontinued Operations (Textuals) [Abstract]
Investment in real estate, net of accumulated depreciation	448,900,000		448,900,000
Mortgage notes payable					$ 41,400,000