CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Beginning Balances at Dec. 31, 2014	$ 133,628	$ 53	$ 45,355	$ 114,383	$ (17,378)	$ (8,785)
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income	9,433			9,433
Other comprehensive income (loss)	(2,157)					(2,157)
Restricted stock awards	314		314
Distribution of treasury stock for directors' deferred compensation plan	3		(89)		92
Distribution of shares of treasury stock granted for employee restricted stock awards, net	0		(195)		195
Restricted stock units for directors' deferred compensation plan	95		95
Cash dividends declared	(4,843)			(4,843)
Distribution of shares of treasury stock for directors' compensation	271		24		247
Distribution of shares of treasury stock for employee compensation	93		8		85
Sale of shares of treasury stock	438		25		413
Repurchase of shares of common stock	(33)				(33)
Ending Balances at Dec. 31, 2015	137,242	53	45,537	118,973	(16,379)	(10,942)
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income	10,027			10,027
Other comprehensive income (loss)	188					188
Restricted stock awards	192		192
Distribution of treasury stock for directors' deferred compensation plan	3		(92)		95
Distribution of shares of treasury stock granted for employee restricted stock awards, net	0		(212)		212
Restricted stock units for directors' deferred compensation plan	97		97
Cash dividends declared	(4,889)			(4,889)
Distribution of shares of treasury stock for directors' compensation	262		19		243
Distribution of shares of treasury stock for employee compensation	210		15		195
Sale of shares of treasury stock	438		47		391
Repurchase of shares of common stock	(22)				(22)
Ending Balances at Dec. 31, 2016	143,748	53	45,603	124,111	(15,265)	(10,754)
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income	7,430			7,430
Other comprehensive income (loss)	2,251					2,251
Restricted stock awards	210		210
Distribution of treasury stock for directors' deferred compensation plan	11		(51)		62
Distribution of shares of treasury stock granted for employee restricted stock awards, net	0		(260)		260
Restricted stock units for directors' deferred compensation plan	98		98
Cash dividends declared	(4,925)			(4,925)
Distribution of shares of treasury stock for directors' compensation	269		68		201
Distribution of shares of treasury stock for employee compensation	200		50		150
Sale of shares of treasury stock	582		206		376
Repurchase of shares of common stock	(61)				(61)
Forfeiture of 1,139 shares of restricted stock awards	0		43		(43)
Reclassification of stranded tax effects in AOCI	0			1,837		(1,837)
Ending Balances at Dec. 31, 2017	$ 149,813	$ 53	$ 45,967	$ 128,453	$ (14,320)	$ (10,340)