Stockholders' Equity - Summary of common shareholders' equity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	$ 28,165	$ 27,117
Balance (shares)	2,614,506
Net Income	$ 3,498	1,317
Retirement benefits adjustment	67	(12)
Compensation expense	101	101
Purchase of treasury shares	(175)	(195)
Cash dividend	(413)	(376)
Stock based compensation, net of tax benefit	270	213
Balance	$ 31,513	$ 28,165
Balance (shares)	2,614,506	2,614,506
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	$ 523	$ 523
Balance (shares)	2,614,506	2,614,506
Balance	$ 523	$ 523
Balance (shares)	2,614,506	2,614,506
Capital in excess of par value
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	$ 14,171	$ 14,160
Stock based compensation, net of tax benefit	79	11
Balance	14,250	14,171
Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	15,709	14,768
Net Income	3,498	1,317
Cash dividend	(413)	(376)
Stock based compensation, net of tax benefit	(6)
Balance	18,788	15,709
ESOT
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	(662)	(763)
Compensation expense	101	101
Balance	(561)	(662)
Treasury stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	(1,544)	(1,551)
Purchase of treasury shares	(175)	(195)
Stock based compensation, net of tax benefit	197	202
Balance	(1,522)	(1,544)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	(32)	(20)
Retirement benefits adjustment	67	(12)
Balance	$ 35	$ (32)