CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]
Common stock, shares outstanding at Dec. 31, 2021		17,331,000
Shareholders' equity at Dec. 31, 2021	$ 564,808	$ 1,085	$ 126,511	$ 458,310	$ (19,981)	$ (1,117)
Net income	55,108			55,108
Total other comprehensive income (loss), net of tax	(151,774)				(151,774)
Cash dividends declared	(28,255)			(28,255)
Share-based compensation	2,589		2,589
Exercise of stock options and issuance of other compensation-related equity awards, net of awards surrendered, shares		34,000
Exercise of stock options and issuance of other compensation-related equity awards, net of awards surrendered, value	(723)	$ 0	(2,045)			1,322
Treasury stock repurchased		(194,000)
Treasury stock purchased under Stock Repurchase Program, amount acquired	(9,479)					(9,479)
Common stock, shares outstanding at Sep. 30, 2022		17,171,000
Shareholders' equity at Sep. 30, 2022	432,274	$ 1,085	127,055	485,163	(171,755)	(9,274)
Common stock, shares outstanding at Jun. 30, 2022		17,190,000
Shareholders' equity at Jun. 30, 2022	476,634	$ 1,085	126,079	475,889	(118,041)	(8,378)
Net income	18,668			18,668
Total other comprehensive income (loss), net of tax	(53,714)				(53,714)
Cash dividends declared	(9,394)			(9,394)
Share-based compensation	976		976
Treasury stock repurchased		(19,000)
Treasury stock purchased under Stock Repurchase Program, amount acquired	(896)					(896)
Common stock, shares outstanding at Sep. 30, 2022		17,171,000
Shareholders' equity at Sep. 30, 2022	$ 432,274	$ 1,085	127,055	485,163	(171,755)	(9,274)
Common stock, shares outstanding at Dec. 31, 2022	17,182,753	17,183,000
Shareholders' equity at Dec. 31, 2022	$ 453,669	$ 1,085	127,056	492,043	(157,800)	(8,715)
Net income	35,229			35,229
Total other comprehensive income (loss), net of tax	(20,934)				(20,934)
Cash dividends declared	(28,751)			(28,751)
Share-based compensation	1,569		1,569
Exercise of stock options and issuance of other compensation-related equity awards, net of awards surrendered, shares		36,000
Exercise of stock options and issuance of other compensation-related equity awards, net of awards surrendered, value	(637)	$ 0	(2,315)			1,678
Treasury stock repurchased		(200,000)
Treasury stock purchased under Stock Repurchase Program, amount acquired	$ (8,741)					(8,741)
Common stock, shares outstanding at Sep. 30, 2023	17,019,239	17,019,000
Shareholders' equity at Sep. 30, 2023	$ 431,404	$ 1,085	126,310	498,521	(178,734)	(15,778)
Common stock, shares outstanding at Jun. 30, 2023		17,019,000
Shareholders' equity at Jun. 30, 2023	459,161	$ 1,085	125,685	496,996	(148,827)	(15,778)
Net income	11,161			11,161
Total other comprehensive income (loss), net of tax	(29,907)				(29,907)
Cash dividends declared	(9,636)			(9,636)
Share-based compensation	624		624
Exercise of stock options and issuance of other compensation-related equity awards, net of awards surrendered, shares		0
Exercise of stock options and issuance of other compensation-related equity awards, net of awards surrendered, value	$ 1	$ 0	1			0
Common stock, shares outstanding at Sep. 30, 2023	17,019,239	17,019,000
Shareholders' equity at Sep. 30, 2023	$ 431,404	$ 1,085	$ 126,310	$ 498,521	$ (178,734)	$ (15,778)