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, 2015	$ 4,659	$ 38,778	$ 78,517	$ (3,722)	$ (6,856)	$ 111,376
Net income			6,363			6,363
Other comprehensive income				1,175		1,175
Cash dividends declared			(2,618)			(2,618)
Acquisition of 30,196 shares of treasury stock					(700)	(700)
Treasury shares issued under employee stock option/purchase plans		2			10	12
Treasury shares issued under dividend reinvestment plan		134			438	572
Common stock issued under dividend reinvestment plan, 25,230 shares	25	527				552
Common stock issued under incentive stock option plan, 3,600 shares	4	55				59
Stock option compensation expense		88				88
Balance at Sep. 30, 2016	4,688	39,584	82,262	(2,547)	(7,108)	116,879
Balance at Dec. 31, 2016	4,688	39,752	83,081	(4,215)	(6,813)	116,493
Net income			9,439			9,439
Other comprehensive income				608		608
Cash dividends declared			(2,988)			(2,988)
Treasury shares issued under employee stock option/purchase plans		29			120	149
Treasury shares issued under dividend reinvestment plan		296			422	718
Stock option compensation expense		161				161
Balance at Sep. 30, 2017	$ 4,688	$ 40,238	$ 89,532	$ (3,607)	$ (6,271)	$ 124,580