Consolidated Statements Of Changes In Shareholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2016	$ 4,688	$ 39,752	$ 83,081	$ (4,215)	$ (6,813)	$ 116,493
Net income			3,020			3,020
Other comprehensive income				299		299
Cash dividends declared			(907)			(907)
Treasury shares issued under employee stock purchase plan		4			21	25
Treasury shares issued under dividend reinvestment plan		84			137	221
Stock option compensation expense		27				27
Balance at Mar. 31, 2017	4,688	39,867	85,194	(3,916)	(6,655)	119,178
Balance at Dec. 31, 2017	4,689	40,396	82,218	(6,028)	(6,131)	115,144
Cumulative adjustment for fair value of equity securities			201	(201)
Net income			3,502			3,502
Other comprehensive income				(781)		(781)
Cash dividends declared			(1,045)			(1,045)
Acquisition of 2,605 shares of treasury stock					(88)	(88)
Treasury shares issued under employee stock purchase plan		2			4	6
Treasury shares issued under dividend reinvestment plan		97			109	206
Common stock issued under incentive stock option plan, 6,518	7	142				149
Stock option compensation expense		31				31
Balance at Mar. 31, 2018	$ 4,696	$ 40,668	$ 84,876	$ (7,010)	$ (6,106)	$ 117,124