CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common stock amount	Additional paid-in capital	Retained earnings impact of ASC 326	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock	impact of ASC 326	Total
Balance at beginning of period at Dec. 31, 2018	$ 32,857	$ 187,653		$ 166,526	$ (11,802)	$ (4,655)		$ 370,579
Increase (Decrease) in Stockholders' Equity
Net income				22,620				22,620
Other comprehensive income					15,594			15,594
Cash dividends declared				(13,366)				(13,366)
Treasury stock purchased						(239)		(239)
Net issuance to employee stock plans, including related tax effects		(490)				217		(273)
Recognition of stock based compensation		1,373						1,373
Balance at end of period at Dec. 31, 2019	32,857	188,536		175,780	3,792	(4,677)		396,288
Increase (Decrease) in Stockholders' Equity
Net income				33,244				33,244
Other comprehensive income					2,948			2,948
Cash dividends declared				(13,417)				(13,417)
Treasury stock purchased						(14,188)		(14,188)
Net issuance to employee stock plans, including related tax effects		(22)				642		620
Recognition of stock based compensation		1,570						1,570
Balance at end of period at Dec. 31, 2020	32,857	190,084		195,607	6,740	(18,223)		407,065
Increase (Decrease) in Stockholders' Equity
Net income				39,299				39,299
Other comprehensive income					(4,437)			(4,437)
Cash dividends declared				(14,072)				(14,072)
Net issuance to employee stock plans, including related tax effects		(1,357)				742		(615)
Recognition of stock based compensation		2,149						2,149
Balance at end of period (Accounting Standards Update 2016-13) at Dec. 31, 2021			$ (5,242)				$ (5,242)
Balance at end of period at Dec. 31, 2021	$ 32,857	$ 190,876		$ 215,592	$ 2,303	$ (17,481)		$ 424,147