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			5,271			5,271
Other comprehensive income (loss)				(4,973)		(4,973)
Cash dividends			(3,304)			(3,304)
Stock-based compensation		110				110
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 Sep. 30, 2021	$ 5,151	24,960	47,063	(1,455)	(2,616)	73,103
Ending balance, shares at Sep. 30, 2021	5,000,026
Beginning balance at Jun. 30, 2021	$ 5,151	24,922	46,266	26	(2,616)	73,749
Beginning balance, shares at Jun. 30, 2021	5,000,026
Net income			1,897			1,897
Other comprehensive income (loss)				(1,481)		(1,481)
Cash dividends			(1,100)			(1,100)
Stock-based compensation		38				38
Ending balance at Sep. 30, 2021	$ 5,151	24,960	47,063	(1,455)	(2,616)	73,103
Ending balance, shares at Sep. 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			6,218			$ 6,218
Other comprehensive income (loss)				(39,515)		(39,515)
Cash dividends			(3,300)			(3,300)
Stock-based compensation		146				146
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 Sep. 30, 2022	$ 5,151	24,956	50,216	(42,880)	(2,538)	$ 34,905
Ending balance, shares at Sep. 30, 2022	5,003,059					5,003,059
Beginning balance at Jun. 30, 2022	$ 5,151	24,926	49,196	(30,310)	(2,538)	$ 46,425
Beginning balance, shares at Jun. 30, 2022	5,003,059
Net income			2,120			2,120
Other comprehensive income (loss)				(12,570)		(12,570)
Cash dividends			(1,100)			(1,100)
Stock-based compensation		30				30
Ending balance at Sep. 30, 2022	$ 5,151	$ 24,956	$ 50,216	$ (42,880)	$ (2,538)	$ 34,905
Ending balance, shares at Sep. 30, 2022	5,003,059					5,003,059