Shareholders' Equity - Summary of common shareholders' equity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Shareholders' Equity
Beginning balance	$ 35,366	$ 33,737
Retirement benefits adjustment	1,672	(2,451)
Stock based compensation	191	106
Purchase of treasury shares		(81)
Net (Loss) Income	(2,117)	4,055
Ending balance	35,112	35,366
Retained earnings
Shareholders' Equity
Beginning balance	25,858	21,803
Net (Loss) Income	(2,117)	4,055
Ending balance	23,741	25,858
Accumulated Other Comprehensive Loss
Shareholders' Equity
Beginning balance	(3,908)	(1,356)
Retirement benefits adjustment	1,571	(2,552)
Ending balance	(2,337)	(3,908)
Common Stock
Shareholders' Equity
Beginning balance	523	523
Ending balance	523	523
Capital in excess of par value
Shareholders' Equity
Beginning balance	14,500	14,481
Stock based compensation	56	19
Ending balance	14,556	14,500
ESOT
Shareholders' Equity
Beginning balance	(258)	(359)
Retirement benefits adjustment	101	101
Ending balance	(157)	(258)
Treasury stock
Shareholders' Equity
Beginning balance	(1,349)	(1,355)
Stock based compensation	135	87
Purchase of treasury shares		(81)
Ending balance	$ (1,214)	$ (1,349)