Shareholders' Equity - Summary of common shareholders' equity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
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	$ 14,068	$ 14,024
Stock based compensation	24	44
Balance	14,092	14,068
Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	9,176	12,302
Net (loss) income	4,597	(3,126)
Cash dividend	(375)
Exercise of stock options, net of tax benefit	(3)
Balance	13,395	9,176
ESOT
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	(964)	(1,065)
Compensation expense	101	101
Balance	(863)	(964)
Treasury stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	(1,909)	(2,024)
Purchase of treasury shares	(114)	(202)
Stock based compensation	314	317
Exercise of stock options, net of tax benefit	7
Balance	(1,702)	(1,909)
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	(14)	(26)
Retirement benefits adjustment	11	12
Balance	(3)	(14)
Balance	20,880	23,734
Net (loss) income	4,597	(3,126)
Retirement benefits adjustment	11	12
Compensation expense	101	101
Purchase of treasury shares	(114)	(202)
Stock based compensation	338	361
Cash dividend	(375)
Exercise of stock options, net of tax benefit	4
Balance	$ 25,442	$ 20,880
Balance (shares)	2,614,506	2,614,506