UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Contributed Capital	Retained Earnings
Beginning balance at Dec. 31, 2016	$ 151,312	$ 422	$ 11,693	$ 139,197
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (losses)	(860)			(860)
Dividends declared:
Common stock, $0.22/share	(928)			(928)
Ending balance at Mar. 31, 2017	149,524	422	11,693	137,409
Beginning balance at Dec. 31, 2016	151,312	422	11,693	139,197
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (losses)	(4,175)
Ending balance at Sep. 30, 2017	144,353	422	11,693	132,238
Beginning balance at Mar. 31, 2017	149,524	422	11,693	137,409
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (losses)	(282)			(282)
Dividends declared:
Common stock, $0.22/share	(928)			(928)
Ending balance at Jun. 30, 2017	148,314	422	11,693	136,199
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (losses)	(3,033)			(3,033)
Dividends declared:
Common stock, $0.22/share	(928)			(928)
Ending balance at Sep. 30, 2017	144,353	422	11,693	132,238
Beginning balance at Dec. 31, 2017	147,119	422	11,693	135,004
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (losses)	1,138			1,138
Dividends declared:
Common stock, $0.22/share	(928)			(928)
Ending balance at Mar. 31, 2018	147,329	422	11,693	135,214
Beginning balance at Dec. 31, 2017	147,119	422	11,693	135,004
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (losses)	6,793
Ending balance at Sep. 30, 2018	151,267	422	11,837	139,008
Beginning balance at Mar. 31, 2018	147,329	422	11,693	135,214
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (losses)	3,620			3,620
Stock-based compensation expense	3		3
Dividends declared:
Common stock, $0.22/share	(928)			(928)
Ending balance at Jun. 30, 2018	150,024	422	11,696	137,906
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (losses)	2,035			2,035
Stock-based compensation expense	141		141
Dividends declared:
Common stock, $0.22/share	(928)			(928)
Awards under LTIP, $0.22/share	(5)			(5)
Ending balance at Sep. 30, 2018	$ 151,267	$ 422	$ 11,837	$ 139,008