Condensed Consolidated Statements of Changes in Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Capital in excess of par value	Cumulative net income	Cumulative dividends	Accumulated other comprehensive income/(loss)
Balance at Dec. 31, 2017	$ 210,561	$ 137	$ 265,335	$ 618,120	$ (673,175)	$ 144
Balance, Shares at Dec. 31, 2017		13,735
Shares of Beneficial Interest:
Issued	29		29
Issued (in shares)		1
Restricted stock-based compensation expense	147		147
Dividends ($.675/share) in 2019 and ($.665/share) in 2018	(9,134)				(9,134)
Comprehensive income:
Net income	9,604			9,604
Unrealized loss on interest rate cap	149					149
Subtotal - comprehensive income	9,753			9,604		149
Balance at Mar. 31, 2018	211,356	$ 137	265,511	627,724	(682,309)	293
Balance, Shares at Mar. 31, 2018		13,736
Balance at Dec. 31, 2018	198,610	$ 137	266,031	642,316	(710,006)	132
Balance, Shares at Dec. 31, 2018		13,747
Shares of Beneficial Interest:
Issued	57		57
Issued (in shares)		1
Restricted stock-based compensation expense	159		159
Dividends ($.675/share) in 2019 and ($.665/share) in 2018	(9,279)				(9,279)
Comprehensive income:
Net income	4,212			4,212
Unrealized loss on interest rate cap	(132)					(132)
Subtotal - comprehensive income	4,080			4,212		$ (132)
Balance at Mar. 31, 2019	$ 193,627	$ 137	$ 266,247	$ 646,528	$ (719,285)
Balance, Shares at Mar. 31, 2019		13,748