Condensed Consolidated Statements of Equity (USD $) In Thousands, unless otherwise specified	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Treasury Stock	Distributions in Excess of Net Income	Stockholders' Investment	Nonredeemable Noncontrolling Interests
Beginning Balance at Dec. 31, 2010	$ 792,851	$ 169,602	$ 106,962	$ 684,551	$ (86,840)	$ (114,196)	$ 760,079	$ 32,772
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(4,876)					(6,109)	(6,109)	1,233
Common stock issued pursuant to:
Stock Granted During Period, Value, Share-based Compensation, Net of Forfeitures	707		82	625			707
Restricted stock grants, net of amounts withheld for income taxes	(19)		244	(263)			(19)
Amortization of stock options and restricted stock, net of forfeitures	1,186		(4)	1,190			1,186
Change in fair value of redeemable noncontrolling interests	(526)			(526)			(526)
Distributions to noncontrolling interests	(1,126)							(1,126)
Cash preferred dividends paid	(6,454)					(6,454)	(6,454)
Cash common dividends paid	(9,316)					(9,316)	(9,316)
Ending Balance at Jun. 30, 2011	772,427	169,602	107,284	685,577	(86,840)	(136,075)	739,548	32,879
Beginning Balance at Dec. 31, 2011	637,395	169,602	107,272	687,835	(86,840)	(274,177)	603,692	33,703
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	900					(257)	(257)	1,157
Common stock issued pursuant to:
Stock Granted During Period, Value, Share-based Compensation, Net of Forfeitures	540		72	468			540
Restricted stock grants, net of amounts withheld for income taxes	(169)		448	(617)			(169)
Amortization of stock options and restricted stock, net of forfeitures	1,210		(7)	1,217			1,210
Change in fair value of redeemable noncontrolling interests	0
Distributions to noncontrolling interests	(1,152)							(1,152)
Cash preferred dividends paid	(6,454)					(6,454)	(6,454)
Cash common dividends paid	(9,373)					(9,373)	(9,373)
Ending Balance at Jun. 30, 2012	$ 622,897	$ 169,602	$ 107,785	$ 688,903	$ (86,840)	$ (290,261)	$ 589,189	$ 33,708