Stockholders' Equity - Summary of common shareholders' equity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	$ 523
Balance (shares)	2,614,506
Net income
Purchase of treasury shares
Dividend payable
Stock based compensation, net of tax benefit
Balance	$ 523
Balance (shares)	2,614,506
Capital in excess of par value
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	$ 14,092
Net income
Purchase of treasury shares
Dividend payable
Stock based compensation, net of tax benefit	$ 13
Balance	14,105
Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	13,395
Net income	$ 258
Purchase of treasury shares
Dividend payable	$ (371)
Stock based compensation, net of tax benefit
Balance	$ 13,282
ESOT
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	$ (863)
Net income
Purchase of treasury shares
Dividend payable
Stock based compensation, net of tax benefit
Balance	$ (863)
Treasury stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	$ (1,702)
Net income
Purchase of treasury shares	$ (165)
Dividend payable
Stock based compensation, net of tax benefit	$ 79
Balance	(1,788)
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance	$ (3)
Net income
Purchase of treasury shares
Dividend payable
Stock based compensation, net of tax benefit
Balance	$ (3)
Balance	$ 25,442
Balance (shares)	2,614,506
Net income	$ 258	$ 2,771
Purchase of treasury shares	(165)
Dividend payable	(371)
Stock based compensation, net of tax benefit	92
Balance	$ 25,256
Balance (shares)	2,614,506