Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]
Balance at Dec. 31, 2014	$ 86,354	$ 2,176	$ 14,819	$ 70,928	$ 907	$ (2,476)
Balance (in shares) at Dec. 31, 2014		3,316,658
Net income	8,233			8,233
Other comprehensive loss, net of tax	(1,453)				(1,453)
Cash dividends declared	(3,872)			(3,872)
Stock issued in connection with dividend reinvestment and stock purchase plan	871	$ 19	852
Stock issued in connection with dividend reinvestment and stock purchase plan (in shares)		30,667
Stock issued for employee stock purchase plan	$ 83	$ 2	81
Stock issued for employee stock purchase (in shares)	3,186	3,186
Stock issued for options exercised	$ 121	$ 6	115
Stock issued for options exercised (in shares)	13,750	9,283
Tax benefit of stock options exercised	$ 21		21
Stock-based compensation expense	85		85
Balance at Dec. 31, 2015	90,443	$ 2,203	15,973	75,289	(546)	(2,476)
Balance (in shares) at Dec. 31, 2015		3,359,794
Net income	8,924			8,924
Other comprehensive loss, net of tax	(3,211)				(3,211)
Cash dividends declared	(4,066)			(4,066)
Stock issued in connection with dividend reinvestment and stock purchase plan	983	$ 19	964
Stock issued in connection with dividend reinvestment and stock purchase plan (in shares)		31,595
Stock issued for employee stock purchase plan	$ 81	$ 2	79
Stock issued for employee stock purchase (in shares)	2,932	2,932
Stock issued for options exercised	$ 308	$ 11	297
Stock issued for options exercised (in shares)	22,700	17,380
Tax benefit of stock options exercised	$ 17		17
Stock-based compensation expense	88		88
Balance at Dec. 31, 2016	$ 93,567	$ 2,235	17,418	80,147	(3,757)	(2,476)
Balance (in shares) at Dec. 31, 2016	3,411,701	3,411,701
Net income	$ 8,289			8,289
Other comprehensive loss, net of tax	(329)				(329)
Cash dividends declared	(4,253)			(4,253)
Stock issued in connection with dividend reinvestment and stock purchase plan	973	$ 16	957
Stock issued in connection with dividend reinvestment and stock purchase plan (in shares)		25,048
Stock issued for employee stock purchase plan	$ 91	$ 2	89
Stock issued for employee stock purchase (in shares)	2,660	2,660
Stock issued for options exercised	$ 130	$ 5	125
Stock issued for options exercised (in shares)	13,125	8,699
Stock-based compensation expense	$ 102		102
Balance at Dec. 31, 2017	$ 98,570	$ 2,258	$ 18,691	$ 84,183	$ (4,086)	$ (2,476)
Balance (in shares) at Dec. 31, 2017	3,448,108	3,448,108