Summary of Quarterly Financial Data (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011
Revenues included in Discontinued Operations	$ 122,002	$ 119,432	$ 129,243	$ 126,243	$ 123,596	$ 122,419	$ 124,038	$ 123,045
Net (loss) income attributable to common stockholders	(37,179)	11,637	5,697	13,181	8,139	8,510	12,861	2,185
Net Income (Loss) Attributable to Noncontrolling Interest, Operating Partnerships	(10)	39	23	54	26	27	37	13
Net Income (Loss) Attributable to Common Unit Holders	(37,189)	11,676	5,720	13,235	8,165	8,537	12,898	2,198
Earnings Per Share, Basic	$ (0.41)	$ 0.13	$ 0.06	$ 0.14	$ 0.10	$ 0.09	$ 0.14	$ 0.02
Earnings Per Share, Diluted	$ (0.41)	$ 0.13	$ 0.06	$ 0.14	$ 0.10	$ 0.09	$ 0.14	$ 0.02
Scenario, Previously Reported [Member]
Revenues included in Discontinued Operations	122,002	120,013	129,767	127,389	125,322	125,747	128,382	127,114
Restatement Adjustment [Member]
Revenues included in Discontinued Operations	$ 0	$ (581)	$ (524)	$ (1,146)	$ (1,726)	$ (3,328)	$ (4,344)	$ (4,069)