Condensed Consolidated Statements of Operations and Comprehensive Loss (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Rental revenue	$ 111,200	$ 108,986	$ 328,517	$ 343,886
Expenses
Property operating expenses	34,094	33,740	100,040	100,927
Interest expense	33,991	33,990	100,079	102,837
Real estate taxes	16,295	16,044	48,731	46,397
Property management fees	3,109	3,261	9,602	10,034
Asset management fees	436	4,452	9,965	13,452
Asset impairment losses	8,301	41,267	24,487	47,794
General and administrative	5,402	2,503	10,999	8,013
Depreciation and amortization	46,694	48,337	141,987	154,082
Total expenses	148,322	183,594	445,890	483,536
Interest and other income	453	171	629	3,314
Gain on troubled debt restructuring			201	1,008
Loss from continuing operations before income taxes, equity in earnings of investments and gain on sale or transfer of assets	(36,669)	(74,437)	(116,543)	(135,328)
Benefit (provision) for income taxes	546	(128)	30	(183)
Equity in earnings (losses) of investments	398	(2,779)	1,327	(2,186)
Loss from continuing operations before gain on sale or transfer of assets	(35,725)	(77,344)	(115,186)	(137,697)
Discontinued operations
Income (loss) from discontinued operations	(612)	(43,139)	1,682	(56,870)
Gain on sale or transfer of discontinued operations	5,041	15,347	19,868	15,986
Income (loss) from discontinued operations	4,429	(27,792)	21,550	(40,884)
Gain on sale or transfer of assets			362	1,385
Net loss	(31,296)	(105,136)	(93,274)	(177,196)
Noncontrolling interests in continuing operations	75	117	175	352
Noncontrolling interests in discontinued operations	(6)	34	(31)	43
Net loss attributable to common stockholders	(31,227)	(104,985)	(93,130)	(176,801)
Basic and diluted weighted average common shares outstanding (in shares)	298,617,928	296,578,847	298,127,216	296,107,513
Basic and diluted income (loss) per common share:
Continuing operations (in dollars per share)	$ (0.11)	$ (0.26)	$ (0.38)	$ (0.46)
Discontinued operations (in dollars per share)	$ 0.01	$ (0.09)	$ 0.07	$ (0.14)
Basic and diluted loss per common share (in dollars per share)	$ (0.10)	$ (0.35)	$ (0.31)	$ (0.60)
Amounts attributable to common stockholders:
Continuing operations	(35,650)	(77,227)	(114,649)	(135,960)
Discontinued operations	4,423	(27,758)	21,519	(40,841)
Net loss attributable to common stockholders	(31,227)	(104,985)	(93,130)	(176,801)
Comprehensive loss:
Net loss	(31,296)	(105,136)	(93,274)	(177,196)
Other comprehensive loss:
Unrealized loss on interest rate derivatives	(543)	(277)	(986)	(277)
Comprehensive loss	(31,839)	(105,413)	(94,260)	(177,473)
Comprehensive loss attributable to noncontrolling interests	104	151	145	395
Comprehensive loss attributable to common stockholders	$ (31,735)	$ (105,262)	$ (94,115)	$ (177,078)