Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Capital	Retained Earnings	Accumulated  Other Comprehensive Income (Loss)	Treasury Stock
Beginning Balance, Shares at Dec. 31, 2020		5,173,000
Beginning Balance, Value at Dec. 31, 2020	$ 203,228	$ 5,173	$ 32,965	$ 166,165	$ (707)	$ (368)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	17,882			17,882
Dividends paid ($4.50 per common share)	(23,050)			(23,050)
Change in fair value of interest rate derivatives	5,198				5,198
Ending Balance, Shares at Mar. 31, 2021		5,173,000
Ending Balance, Value at Mar. 31, 2021	$ 203,258	$ 5,173	32,965	160,997	4,491	(368)
Beginning Balance, Shares at Dec. 31, 2021	5,173,450	5,173,000
Beginning Balance, Value at Dec. 31, 2021	$ 252,589	$ 5,173	33,415	206,875	7,494	(368)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	14,532			14,532
Dividends paid ($4.50 per common share)	(23,060)			(23,060)
Change in fair value of interest rate derivatives	$ 11,727				11,727
Ending Balance, Shares at Mar. 31, 2022	5,173,450	5,173,000
Ending Balance, Value at Mar. 31, 2022	$ 255,788	$ 5,173	$ 33,415	$ 198,347	$ 19,221	$ (368)