CONSOLIDATED STATEMENTS OF EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Shares of Beneficial Interest, $1.00 Par	Capital Contributed in Excess of Par	Accumulated Other Comprehensive Loss	Distributions in Excess of Net Income	Non- controlling interest	Series B Preferred Stock	Series B Preferred Stock Preferred Shares $.01 par	Series B Preferred Stock Distributions in Excess of Net Income	Series C Preferred Stock	Series C Preferred Stock Preferred Shares $.01 par	Series C Preferred Stock Distributions in Excess of Net Income	Series D Preferred Stock	Series D Preferred Stock Preferred Shares $.01 par	Series D Preferred Stock Distributions in Excess of Net Income
Beginning balance at Dec. 31, 2019	$ 427,425	$ 77,550	$ 1,766,883	$ (12,556)	$ (1,408,352)	$ 3,746		$ 35			$ 69			$ 50
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(13,549)				(13,033)	(516)
Other comprehensive income (loss)	(19,746)			(19,240)		(506)
Shares issued under employee compensation plan, net of shares retired	(42)	1,290	(1,332)
Amortization of deferred compensation	1,624		1,624
Dividends paid to common shareholders	(16,492)				(16,492)
Dividends paid to preferred shareholders							$ (1,591)		$ (1,591)	$ (3,105)		$ (3,105)	$ (2,148)		$ (2,148)
Noncontrolling interests:
Distributions paid to Operating Partnership unit holders	(411)					(411)
Ending balance at Mar. 31, 2020	371,965	78,840	1,767,175	(31,796)	(1,444,721)	2,313		35			69			50
Beginning balance at Dec. 31, 2020	126,940	79,537	1,771,777	(20,620)	(1,699,638)	(4,270)		35			69			50
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(43,980)				(42,746)	(1,234)
Other comprehensive income (loss)	2,604			2,540		64
Shares issued under employee compensation plan, net of shares retired	(647)	(277)	(370)
Amortization of deferred compensation	1,321		1,321
Ending balance at Mar. 31, 2021	$ 86,238	$ 79,260	$ 1,772,728	$ (18,080)	$ (1,742,384)	$ (5,440)		$ 35			$ 69			$ 50