Condensed Consolidated Statements of Changes in Equity - USD ($) $ 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, 2020	$ 159,005	$ 138	$ 267,368	$ 680,727	$ (785,413)	$ (3,815)
Balance, Shares at Dec. 31, 2020		13,771
Shares of Beneficial Interest:
Issued	57		57
Issued (in shares)		1
Restricted stock-based compensation expense	242		242
Dividends	(9,571)				(9,571)
Comprehensive income:
Net income	5,586			5,586
Unrealized net gain (loss) on cash flow hedges	3,348					3,348
Subtotal - comprehensive income	8,934			5,586		3,348
Balance at Mar. 31, 2021	158,667	$ 138	267,667	686,313	(794,984)	(467)
Balance, Shares at Mar. 31, 2021		13,772
Balance at Dec. 31, 2021	235,327	$ 138	268,515	789,559	(823,998)	1,113
Balance, Shares at Dec. 31, 2021		13,785
Shares of Beneficial Interest:
Issued	54		54
Issued (in shares)		1
Restricted stock-based compensation expense	223		223
Dividends	(9,719)				(9,719)
Comprehensive income:
Net income	5,405			5,405
Unrealized net gain (loss) on cash flow hedges	5,684					5,684
Subtotal - comprehensive income	11,089			5,405		5,684
Balance at Mar. 31, 2022	$ 236,974	$ 138	$ 268,792	$ 794,964	$ (833,717)	$ 6,797
Balance, Shares at Mar. 31, 2022		13,786