Stockholders' Equity - Summary of common shareholders' equity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	$ 27,117
Net income	26	$ 258
Purchase of treasury shares	(160)
Stock based compensation, net of tax benefit	54
Balance	$ 27,037
Balance (shares)	2,614,506
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	$ 523
Balance (shares)	2,614,506
Balance	$ 523
Balance (shares)	2,614,506
Capital in excess of par value
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	$ 14,160
Balance	14,160
Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	14,768
Net income	26
Balance	14,794
ESOT
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	(763)
Balance	(763)
Treasury stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	(1,551)
Purchase of treasury shares	(160)
Stock based compensation, net of tax benefit	52
Balance	(1,659)
Accumulated other comprehensive loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	(20)
Balance	$ (20)