Consolidated Statements of Beneficiaries' Equity (USD $) In Thousands, except Share data	Total	Series E Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Deferred Compensation, Share-based Payments [Member]	Common Stock In Grantor Trust [Member]	Cumulative Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Cumulative Distributions [Member]	Noncontrolling Interest [Member]
Beginning Balance at Dec. 31, 2012	$ 1,773,516	$ 40	$ 1,434	$ 2,780,194	$ 5,352	$ (5,352)	$ 479,734	$ (15,918)	$ (1,493,206)	$ 21,238
Beginning Balance, Shares at Dec. 31, 2012		4,000,000	143,538,733		290,745
Net income (loss)	3,919						3,891			28
Comprehensive Income (Loss)	1,893							1,870		23
Equity Issuance Costs	(61)			(61)
Bonus Share Issuance, Shares			27,918
Bonus Share Issuance, Value	361			361
Share Based Compensation Activity, Shares			123,523		7,050
Share Based Compensation Activity, Value	2,666		1	2,655			10
Share Issuance from/to Deferred Compensation Plan, Shares			22,404		17,958
Share issuance from/to Deferred Compensation Plan, Value	0				164	(164)
Adjustments to Non-controlling Interest	0			(19)						19
Preferred Share distributions	(1,725)								(1,725)
Distributions declared ($0.15 per share)	(21,936)								(21,660)	(276)
Ending Balance at Mar. 31, 2013	1,758,633	40	1,435	2,783,130	5,516	(5,516)	483,635	(14,048)	(1,516,591)	21,032
Ending Balance, Shares at Mar. 31, 2013		4,000,000	143,712,578		315,753
Beginning Balance at Dec. 31, 2013	1,921,435	40	1,566	2,971,596	5,407	(5,407)	522,528	(2,995)	(1,592,515)	21,215
Beginning Balance, Shares at Dec. 31, 2013		4,000,000	156,731,993		312,279
Net income (loss)	(2,245)						(2,213)			(32)
Comprehensive Income (Loss)	(920)							(910)		(10)
Equity Issuance Costs	(52)			(52)
Share Based Compensation Activity, Shares			108,347
Share Based Compensation Activity, Value	2,651		1	2,643			7
Share Issuance from/to Deferred Compensation Plan, Shares			76,561		72,292
Share issuance from/to Deferred Compensation Plan, Value	(89)			(89)	860	(860)
Adjustments to Non-controlling Interest	0			(4)						4
Preferred Share distributions	(1,725)								(1,725)
Distributions declared ($0.15 per share)	(23,903)								(23,638)	(265)
Ending Balance at Mar. 31, 2014	$ 1,895,152	$ 40	$ 1,567	$ 2,974,094	$ 6,267	$ (6,267)	$ 520,322	$ (3,905)	$ (1,617,878)	$ 20,912
Ending Balance, Shares at Mar. 31, 2014		4,000,000	156,916,901		384,571