Stockholders' Equity - Summary of common shareholders' equity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at December 31, 2017			$ 28,165
Balance at December 31, 2017 (shares)			2,614,506
Net Income	$ 707	$ 105	$ 1,038	$ 131
Purchase of treasury shares			(150)
Cash dividend			(416)
Stock based compensation, net of tax benefit			85
Balance at June 30, 2018	$ 28,722		$ 28,722
Balance at June 30, 2018 (shares)	2,614,506		2,614,506
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at December 31, 2017			$ 523
Balance at December 31, 2017 (shares)			2,614,506
Purchase of treasury shares			$ 0
Cash dividend			0
Stock based compensation, net of tax benefit			0
Balance at June 30, 2018	$ 523		$ 523
Balance at June 30, 2018 (shares)	2,614,506		2,614,506
Capital in excess of par value
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at December 31, 2017			$ 14,171
Purchase of treasury shares			0
Cash dividend			0
Stock based compensation, net of tax benefit			21
Balance at June 30, 2018	$ 14,192		14,192
Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at December 31, 2017			15,709
Net Income			1,038
Purchase of treasury shares			0
Cash dividend			(416)
Stock based compensation, net of tax benefit			(6)
Balance at June 30, 2018	16,325		16,325
ESOT
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at December 31, 2017			(662)
Purchase of treasury shares			0
Cash dividend			0
Stock based compensation, net of tax benefit			0
Balance at June 30, 2018	(662)		(662)
Treasury stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at December 31, 2017			(1,544)
Purchase of treasury shares			(150)
Cash dividend			0
Stock based compensation, net of tax benefit			64
Balance at June 30, 2018	(1,630)		(1,630)
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at December 31, 2017			(32)
Purchase of treasury shares			0
Cash dividend			0
Stock based compensation, net of tax benefit			6
Balance at June 30, 2018	$ (26)		$ (26)