Real Estate Disposition Activities (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Summary of income from discontinued operations
Rental income	$ 9,469	$ 6,986	$ 27,832
Operating and other expenses	(5,988)	(2,486)	(17,277)
Interest expense, net	(1,311)	(133)	(3,922)
Loss on extinguishment of debt		(602)
Depreciation expense	(1,843)	(895)	(6,002)
Income from discontinued operations	$ 327	$ 2,870	$ 631