Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]	Total
Beginning balance at Dec. 31, 2020	$ 5,151	$ 25,011	$ 45,096	$ 3,518	$ (2,179)	$ 76,597
Beginning balance, shares at Dec. 31, 2020	5,025,441
Net income			3,374			3,374
Other comprehensive income (loss)				(3,492)		(3,492)
Cash dividends			(2,204)			(2,204)
Stock-based compensation		72				72
Purchase of treasury stock					(675)	(675)
Purchase of treasury stock, shares	(39,198)
Treasury stock issued for stock plans		(161)			238	77
Treasury stock issued for stock plans, shares	13,783
Ending balance at Jun. 30, 2021	$ 5,151	24,922	46,266	26	(2,616)	73,749
Ending balance, shares at Jun. 30, 2021	5,000,026
Beginning balance at Mar. 31, 2021	$ 5,151	24,893	45,629	(590)	(2,509)	72,574
Beginning balance, shares at Mar. 31, 2021	5,006,695
Net income			1,739			1,739
Other comprehensive income (loss)				616		616
Cash dividends			(1,102)			(1,102)
Stock-based compensation		37				37
Purchase of treasury stock					(192)	(192)
Purchase of treasury stock, shares	(11,613)
Treasury stock issued for stock plans		(8)			85	77
Treasury stock issued for stock plans, shares	4,944
Ending balance at Jun. 30, 2021	$ 5,151	24,922	46,266	26	(2,616)	73,749
Ending balance, shares at Jun. 30, 2021	5,000,026
Beginning balance at Dec. 31, 2021	$ 5,151	25,008	47,298	(3,365)	(2,802)	$ 71,290
Beginning balance, shares at Dec. 31, 2021	4,988,542					4,988,542
Net income			4,098			$ 4,098
Other comprehensive income (loss)				(26,945)		(26,945)
Cash dividends			(2,200)			(2,200)
Stock-based compensation		116				116
Purchase of treasury stock					(3)	(3)
Purchase of treasury stock, shares	(995)
Treasury stock issued for stock plans		(198)			267	69
Treasury stock issued for stock plans, shares	15,512
Ending balance at Jun. 30, 2022	$ 5,151	24,926	49,196	(30,310)	(2,538)	$ 46,425
Ending balance, shares at Jun. 30, 2022	5,003,059					5,003,059
Beginning balance at Mar. 31, 2022	$ 5,151	24,864	48,313	(18,979)	(2,624)	$ 56,725
Beginning balance, shares at Mar. 31, 2022	4,998,858
Net income			1,983			1,983
Other comprehensive income (loss)				(11,331)		(11,331)
Cash dividends			(1,100)			(1,100)
Stock-based compensation		79				79
Purchase of treasury stock, shares	(825)
Treasury stock issued for stock plans		(17)			86	69
Treasury stock issued for stock plans, shares	5,026
Ending balance at Jun. 30, 2022	$ 5,151	$ 24,926	$ 49,196	$ (30,310)	$ (2,538)	$ 46,425
Ending balance, shares at Jun. 30, 2022	5,003,059					5,003,059