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, 2020		17,265,000
Shareholders' equity at Dec. 31, 2020	$ 534,195	$ 1,085	$ 125,610	$ 418,246	$ (7,391)	$ (3,355)
Net income	37,931			37,931
Total other comprehensive income (loss), net of tax	(7,737)				(7,737)
Cash dividends declared	(18,250)			(18,250)
Share-based compensation	1,882		1,882
Exercise of stock options and issuance of other compensation-related equity awards, net of awards surrendered, shares		55,000
Exercise of stock options and issuance of other compensation-related equity awards, net of awards surrendered, value	(165)	$ 0	(2,050)			1,885
Common stock, shares outstanding at Jun. 30, 2021		17,320,000
Shareholders' equity at Jun. 30, 2021	547,856	$ 1,085	125,442	437,927	(15,128)	(1,470)
Common stock, shares outstanding at Mar. 31, 2021		17,306,000
Shareholders' equity at Mar. 31, 2021	533,599	$ 1,085	124,882	429,598	(20,006)	(1,960)
Net income	17,460			17,460
Total other comprehensive income (loss), net of tax	4,878				4,878
Cash dividends declared	(9,131)			(9,131)
Share-based compensation	964		964
Exercise of stock options and issuance of other compensation-related equity awards, net of awards surrendered, shares		14,000
Exercise of stock options and issuance of other compensation-related equity awards, net of awards surrendered, value	86	$ 0	(404)			490
Common stock, shares outstanding at Jun. 30, 2021		17,320,000
Shareholders' equity at Jun. 30, 2021	$ 547,856	$ 1,085	125,442	437,927	(15,128)	(1,470)
Common stock, shares outstanding at Dec. 31, 2021	17,330,818	17,331,000
Shareholders' equity at Dec. 31, 2021	$ 564,808	$ 1,085	126,511	458,310	(19,981)	(1,117)
Net income	36,440			36,440
Total other comprehensive income (loss), net of tax	(98,060)				(98,060)
Cash dividends declared	(18,861)			(18,861)
Share-based compensation	1,613		1,613
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
Common stock, shares outstanding at Jun. 30, 2022	17,189,901	17,190,000
Shareholders' equity at Jun. 30, 2022	$ 476,634	$ 1,085	126,079	475,889	(118,041)	(8,378)
Treasury stock purchased under Stock Repurchase Program, amount acquired	$ (8,583)					(8,583)
Treasury stock purchased under Stock Repurchase Program, shares acquired	(175,000)
Common stock, shares outstanding at Mar. 31, 2022		17,332,000
Shareholders' equity at Mar. 31, 2022	$ 513,192	$ 1,085	127,355	465,295	(79,451)	(1,092)
Net income	19,957			19,957
Total other comprehensive income (loss), net of tax	(38,590)				(38,590)
Cash dividends declared	(9,363)			(9,363)
Share-based compensation	725		725
Exercise of stock options and issuance of other compensation-related equity awards, net of awards surrendered, shares		33,000
Exercise of stock options and issuance of other compensation-related equity awards, net of awards surrendered, value	$ (704)	$ 0	(2,001)			1,297
Common stock, shares outstanding at Jun. 30, 2022	17,189,901	17,190,000
Shareholders' equity at Jun. 30, 2022	$ 476,634	$ 1,085	$ 126,079	$ 475,889	$ (118,041)	(8,378)
Treasury stock purchased under Stock Repurchase Program, amount acquired	$ (8,583)					$ (8,583)
Treasury stock purchased under Stock Repurchase Program, shares acquired	(175,000)