Condensed Consolidated Statements of Equity (USD $) In Thousands, unless otherwise specified	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Distributions in Excess of Net Income [Member]	Stockholders' Investment [Member]	Nonredeemable Noncontrolling Interests [Member]
Beginning balance at Dec. 31, 2010	$ 792,851	$ 169,602	$ 106,962	$ 684,551	$ (86,840)	$ (114,196)	$ 760,079	$ 32,772
Net Income (Loss) in Statement on Equity	(124,900)	0	0	0	0	(128,425)	(128,425)	3,525
Net Income (Loss) Attributable to Parent	(128,425)
Common stock issued pursuant to:
Director stock grants	707	0	82	625	0	0	707	0
Stock option exercises	18	0	4	14	0	0	18	0
Restricted stock grants, net of amounts withheld for income taxes	(9)	0	243	(252)	0	0	(9)	0
Amortization of stock options and restricted stock, net of forfeitures	2,112	0	(19)	2,131	0	0	2,112	0
Distributions to nonredeemable noncontrolling interests	(3,894)	0	0	0	0	0	0	(3,894)
Contributions from Nonredeemable Noncontrolling Interest	1,300	0	0	0	0	0	0	1,300
Preferred Stock Redemption	0
Change in fair value of redeemable noncontrolling interests	766	0	0	766	0	0	766	0
Cash preferred dividends paid	(12,907)	0	0	0	0	(12,907)	(12,907)	0
Cash common dividends paid	(18,649)	0	0	0	0	(18,649)	(18,649)	0
Ending balance at Dec. 31, 2011	637,395	169,602	107,272	687,835	(86,840)	(274,177)	603,692	33,703
Net Income (Loss) in Statement on Equity	49,922	0	0	0	0	45,728	45,728	4,194
Net Income (Loss) Attributable to Parent	45,728
Common stock issued pursuant to:
Director stock grants	540	0	72	468	0	0	540	0
Restricted stock grants, net of amounts withheld for income taxes	(207)	0	452	(659)	0	0	(207)	0
Amortization of stock options and restricted stock, net of forfeitures	2,244	0	(136)	2,380	0	0	2,244	0
Distributions to nonredeemable noncontrolling interests	(15,286)	0	0	0	0	0	0	(15,286)
Preferred Stock Redemption	0
Change in fair value of redeemable noncontrolling interests	0
Cash preferred dividends paid	(12,907)	0	0	0	0	(12,907)	(12,907)	0
Cash common dividends paid	(18,748)	0	0	0	0	(18,748)	(18,748)	0
Ending balance at Dec. 31, 2012	642,953	169,602	107,660	690,024	(86,840)	(260,104)	620,342	22,611
Net Income (Loss) in Statement on Equity	126,761	0	0	0	0		121,761	5,000
Net Income (Loss) Attributable to Parent	121,761
Common stock issued pursuant to:
Director stock grants	544	0	50	494	0	0	544	0
Stock option exercises	(171)	0	31	(202)	0	0	(171)	0
Common stock offering, net of issuance costs	826,233	0	85,507	740,726	0	0	826,233	0
Restricted stock grants, net of amounts withheld for income taxes	(1,179)	0	30	(1,209)	0	0	(1,179)	0
Amortization of stock options and restricted stock, net of forfeitures	1,898	0	(42)	1,940	0	0	1,898	0
Distributions to nonredeemable noncontrolling interests	(26,040)	0	0	0	0	0	0	(26,040)
Preferred Stock Redemption	(74,827)	(74,827)	0	(10,822)	0	10,822	(74,827)	0
Change in fair value of redeemable noncontrolling interests	0
Cash preferred dividends paid	(10,008)	0	0	0	0	(10,008)	(10,008)	0
Cash common dividends paid	(27,192)	0	0	0	0	(27,192)	(27,192)	0
Ending balance at Dec. 31, 2013	$ 1,458,972	$ 94,775	$ 193,236	$ 1,420,951	$ (86,840)	$ (164,721)	$ 1,457,401	$ 1,571