Condensed Consolidated Statements of Changes in Equity (USD $) In Thousands, unless otherwise specified	Total USD ($)	Common Stock USD ($)	Additional Paid-in Capital USD ($)	Cumulative Distributions and Net Loss Attributable to Common Stockholders USD ($)	Accumulated Other Comprehensive Loss USD ($)	Noncontrolling Interests USD ($)	Comprehensive Loss USD ($)	Convertible Stock
Balance at Dec. 31, 2010	$ 1,166,498					$ 6,247
Balance (in shares) at Dec. 31, 2010								1
Comprehensive loss:
Distributions declared	(7,401)					(12)
Balance at Mar. 31, 2011
Balance at Dec. 31, 2010	1,166,498	29	2,632,290	(1,472,068)		6,247
Balance (in shares) at Dec. 31, 2010		295,276						1
Comprehensive loss:
Net loss	(177,196)			(176,801)		(395)	(177,196)
Unrealized loss on interest rate derivatives	(277)				(277)		(277)
Total comprehensive loss	(177,473)						(177,473)
Redemption of common stock	(3,212)		(3,212)
Redemption of common stock (in shares)		(706)
Distributions declared	(22,245)			(22,207)		(38)
Shares issued pursuant to Distribution Reinvestment Plan	9,984	1	9,983
Shares issued pursuant to Distribution Reinvestment Plan (in shares)		2,194
Cost of share issuance	(11)		(11)
Acquisition of noncontrolling interest	(1,036)		(1,567)			531
Balance at Sep. 30, 2011	972,505	30	2,637,483	(1,671,076)	(277)	6,345
Balance (in shares) at Sep. 30, 2011		296,764						1
Balance at Jun. 30, 2011
Comprehensive loss:
Net loss	(105,136)
Unrealized loss on interest rate derivatives	(277)
Total comprehensive loss	(105,413)
Distributions declared	(7,426)					(12)
Balance at Sep. 30, 2011	972,505					6,345
Balance (in shares) at Sep. 30, 2011								1
Balance at Dec. 31, 2011	961,991					6,299
Comprehensive loss:
Distributions declared	(7,450)					(11)
Balance at Mar. 31, 2012
Balance at Dec. 31, 2011	961,991	30	2,639,720	(1,683,153)	(905)	6,299
Balance (in shares) at Dec. 31, 2011		297,256						1
Comprehensive loss:
Net loss	(93,274)			(93,130)		(144)	(93,274)
Unrealized loss on interest rate derivatives	(986)				(985)	(1)	(986)
Total comprehensive loss	(94,260)						(94,260)
Redemption of common stock	(3,062)		(3,062)
Redemption of common stock (in shares)		(660)
Cancellation of convertible stock (in shares)								(1)
Distributions declared	(22,756)			(22,356)		(400)
Shares issued pursuant to Distribution Reinvestment Plan	9,820		9,820
Shares issued pursuant to Distribution Reinvestment Plan (in shares)		2,116
Cost of share issuance	(9)		(9)
Issuance of Series A Convertible Preferred Stock	(2,700)		(2,700)
Balance at Sep. 30, 2012	849,024	30	2,643,769	(1,798,639)	(1,890)	5,754
Balance (in shares) at Sep. 30, 2012		298,712
Balance at Jun. 30, 2012
Comprehensive loss:
Net loss	(31,296)
Unrealized loss on interest rate derivatives	(543)
Total comprehensive loss	(31,839)
Distributions declared	(7,476)					(11)
Balance at Sep. 30, 2012	$ 849,024					$ 5,754