CONSOLIDATED STATEMENTS OF EQUITY (USD $) In Thousands, unless otherwise specified	Total		Shares of Beneficial Interest, $1.00 Par [Member]	Capital Contributed in Excess of Par [Member]	Accumulated Other Comprehensive (Income) Loss [Member]	Distributions in Excess of Net Income [Member]	Non- controlling interest [Member]	Series A [Member]	Series A [Member] Distributions in Excess of Net Income [Member]	Series B [Member]	Series B [Member] Distributions in Excess of Net Income [Member]	Series A Preferred Shares, $.01 par [Member]	Series A Preferred Shares, $.01 par [Member] Series A [Member]	Series A Preferred Shares, $.01 par [Member] Series A [Member] Capital Contributed in Excess of Par [Member]	Series B Preferred Shares, $.01 par [Member]	Series B Preferred Shares, $.01 par [Member] Series B [Member]	Series B Preferred Shares, $.01 par [Member] Series B [Member] Capital Contributed in Excess of Par [Member]
Beginning Balance at Dec. 31, 2010	$ 704,530		$ 55,436	$ 1,040,023	$ (39,993)	$ (401,193)	$ 50,257
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(93,935)					(90,161)	(3,774)
Comprehensive income	6,142				5,894		248
Shares issued under employee and trustee compensation plans, net of shares retired	(1,350)		241	(1,591)
Amortization of deferred compensation	9,055			9,055
Distributions paid to common shareholders	(33,384)					(33,384)
Distributions paid to preferred shareholders	0
Noncontrolling interests:
Distributions paid to Operating Partnership unit holders	(1,395)						(1,395)
Amortization of historic tax credit	(1,921)						(1,921)
Contributions from noncontrolling interest, net	296						296
Ending Balance at Dec. 31, 2011	588,038		55,677	1,047,487	(34,099)	(524,738)	43,711
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(42,550)	[1]				(40,837)	(1,713)
Comprehensive income	13,789				13,232		557
Shares issued upon redemption of Operating Partnership units	0		28	413			(441)
Shares issued under employee and trustee compensation plans, net of shares retired	(4,722)		626	(5,348)
Share offering								110,896		83,335			46	110,850		35	83,300
Amortization of deferred compensation	11,028			11,028
Distributions paid to common shareholders	(35,735)					(35,735)
Distributions paid to preferred shareholders	(7,984)							(6,193)	(6,193)	(1,131)	(1,131)
Noncontrolling interests:
Distributions paid to Operating Partnership unit holders	(1,459)						(1,459)
Amortization of historic tax credit	(1,810)						(1,810)
Contributions from noncontrolling interest, net	(257)						(257)
Ending Balance at Dec. 31, 2012	713,229		56,331	1,247,730	(20,867)	(608,634)	38,588					46			35
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	37,213	[1]				35,859	1,354
Comprehensive income	14,716				14,230		486
Shares issued upon redemption of Operating Partnership units			172	2,372			(2,544)
Shares issued under employee and trustee compensation plans, net of shares retired	566		290	276
Share offering	220,511		11,500	209,011
Amortization of deferred compensation	8,071			8,071
Distributions paid to common shareholders	(48,315)					(48,315)
Distributions paid to preferred shareholders	(15,848)							(9,488)	(9,488)	(6,361)	(6,361)
Noncontrolling interests:
Distributions paid to Operating Partnership unit holders	(1,626)						(1,626)
Amortization of historic tax credit	(1,810)						(1,810)
Contributions from noncontrolling interest, net	(254)						(254)
Ending Balance at Dec. 31, 2013	$ 926,452		$ 68,293	$ 1,467,460	$ (6,637)	$ (636,939)	$ 34,194					$ 46			$ 35

[1] Includes gains on sales of discontinued operations (before non controlling interest) of $33.4 million (1st Quarter 2013), $45.1 million (3rd Quarter 2013) and $0.9 million (4th Quarter 2012).