Consolidated Statements of Changes in Stockholders' Equity (unaudited) - 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, 2016	$ 24,806	$ 16,427	$ 56,965	$ (4,208)	$ 93,990
Beginning Balance (in shares) at Dec. 31, 2016	4,961,258
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	0	2,860	0	2,860
Other comprehensive income (loss), net of tax	0	0	0	1,521	1,521
Issuance of common stock related to acquisition					0
Exercise of stock options	$ 241	727	0	0	968
Exercise of stock options (in shares)	48,287
Employee Stock Purchase Plan share issuance	$ 13	58	0	0	71
Employee Stock Purchase Plan share issuance (in shares)	2,523
Repurchase and retirement of common stock	$ (23)	(109)	0	0	(132)
Repurchase and retirement of common stock (in shares)	(4,683)
Stock-based compensation expense	$ 0	9	0	0	9
Cash dividends	0	0	(1,646)	0	(1,646)
Ending Balance at Sep. 30, 2017	$ 25,037	17,112	58,179	(2,687)	97,641
Ending Balance (in shares) at Sep. 30, 2017	5,007,385
Beginning Balance at Jun. 30, 2017				(2,744)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income					757
Other comprehensive income (loss), net of tax					57
Ending Balance at Sep. 30, 2017	$ 25,037	17,112	58,179	(2,687)	97,641
Ending Balance (in shares) at Sep. 30, 2017	5,007,385
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of the stranded income tax effects of the Tax Cuts and Jobs Act from AOCI | ASU 2018-02 [Member]	$ 0	0	139	(139)	0
Reclassification of net unrealized gains on equity securities from AOCI per ASU 2016-01 | ASU 2016-01 [Member]	0	0	77	(77)	0
Beginning Balance at Dec. 31, 2017	$ 25,087	17,270	54,738	(707)	$ 96,388
Beginning Balance (in shares) at Dec. 31, 2017	5,017,458				5,019,703
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	0	3,531	0	$ 3,531
Other comprehensive income (loss), net of tax	0	0	0	(2,769)	(2,769)
Issuance of common stock related to acquisition	$ 748	3,199	0	0	3,947
Issuance of common stock related to acquisition (in shares)	149,625
Employee Stock Purchase Plan share issuance	$ 14	52	0	0	66
Employee Stock Purchase Plan share issuance (in shares)	2,644
Stock-based compensation expense	$ 0	103	0	0	103
Cash dividends	0	0	(1,691)	0	(1,691)
Ending Balance at Sep. 30, 2018	$ 25,849	20,624	56,794	(3,692)	$ 99,575
Ending Balance (in shares) at Sep. 30, 2018	5,169,727				5,183,416
Beginning Balance at Jun. 30, 2018				(2,889)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income					$ 1,597
Other comprehensive income (loss), net of tax					(803)
Ending Balance at Sep. 30, 2018	$ 25,849	$ 20,624	$ 56,794	$ (3,692)	$ 99,575
Ending Balance (in shares) at Sep. 30, 2018	5,169,727				5,183,416