Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Total
Beginning Balance at Dec. 31, 2014	$ 24,795	$ 16,392	$ 53,203	$ (5,893)	$ 88,497
Beginning Balance (in shares) at Dec. 31, 2014	4,959,009
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 0	0	3,634	0	3,634
Other comprehensive income (loss) net of tax	0	0	0	2,731	2,731
Cash dividends	0	0	(1,686)	0	(1,686)
Ending Balance at Dec. 31, 2015	$ 24,795	16,392	55,151	(3,162)	93,176
Ending Balance (in shares) at Dec. 31, 2015	4,959,009
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 0	0	3,797	0	3,797
Other comprehensive income (loss) net of tax	0	0	0	(1,046)	(1,046)
Exercise of stock options	$ 6	19	0	0	25
Exercise of stock options (in shares)	1,250
Employee Stock Purchase Plan share issuance	$ 5	16	0	0	21
Employee Stock Purchase Plan share issuance (in shares)	999
Cash dividends	$ 0	0	(1,983)	0	(1,983)
Ending Balance at Dec. 31, 2016	$ 24,806	16,427	56,965	(4,208)	$ 93,990
Ending Balance (in shares) at Dec. 31, 2016	4,961,258				4,961,258
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 0	0	(29)	0	$ (29)
Other comprehensive income (loss) net of tax	0	0	0	3,501	3,501
Exercise of stock options	$ 290	875	0	0	1,165
Exercise of stock options (in shares)	58,105
Employee Stock Purchase Plan share issuance	$ 18	81	0	0	99
Employee Stock Purchase Plan share issuance (in shares)	3,548
Repurchase of common stock related to stock option exercises	$ (27)	(130)	0	0	(157)
Repurchase of common stock related to stock option exercises (in shares)	(5,453)
Stock-based compensation expense	$ 0	17	0	0	17
Cash dividends	0	0	(2,198)	0	(2,198)
Ending Balance at Dec. 31, 2017	$ 25,087	$ 17,270	$ 54,738	$ (707)	$ 96,388
Ending Balance (in shares) at Dec. 31, 2017	5,017,458				5,019,703