Real Estate Disposition Activities (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Summary of income from discontinued operations
Rental income	$ 7,176	$ 10,583	$ 25,321	$ 38,156
Operating and other expenses	(2,229)	(2,995)	(7,521)	(11,718)
Interest expense, net				(133)
Loss on extinguishment of debt				(602)
Depreciation expense	(1,726)	(3,248)	(10,727)	(10,641)
Income from discontinued operations	$ 3,221	$ 4,340	$ 7,073	$ 15,062