Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock	Capital Surplus [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Deferred Benefits for Directors [Member]
Beginning Balance at Dec. 31, 2021	$ 2,693,166	$ 144,484	$ 141,834	$ 1,635,642	$ 977,765	$ (199,759)	$ (5,120)	$ (1,680)
Beginning Balance, shares at Dec. 31, 2021			62,307,245
Net income	139,903				139,903
Other comprehensive loss	(261,520)						(261,520)
Comprehensive income (loss)	(121,617)
Common dividends declared	(60,750)				(60,750)
Preferred dividends declared	(7,594)				(7,594)
Stock issued for dividend reinvestment					(792)	792
Stock issued for dividend reinvestment, shares			23,478
Treasury shares acquired	(113,600)					(113,600)
Treasury shares acquired, shares			(3,250,383)
Stock options exercised	1,629			(384)		2,013
Stock options exercised, shares			59,959
Restricted stock granted				(5,521)		5,521
Restricted stock granted, shares			164,206
Stock compensation expense	4,519			4,519
Deferred benefits for directors- net	(101)			24				(125)
Ending Balance at Sep. 30, 2022	2,395,652	144,484	$ 141,834	1,634,280	1,048,532	(305,033)	(266,640)	(1,805)
Ending Balance, shares at Sep. 30, 2022			59,304,505
Beginning Balance at Jun. 30, 2022	2,467,951	144,484	$ 141,834	1,632,617	1,018,209	(291,337)	(176,061)	(1,795)
Beginning Balance, shares at Jun. 30, 2022			59,698,788
Net income	53,033				53,033
Other comprehensive loss	(90,579)						(90,579)
Comprehensive income (loss)	(37,546)
Common dividends declared	(20,024)				(20,024)
Preferred dividends declared	(2,531)				(2,531)
Stock issued for dividend reinvestment					(155)	155
Stock issued for dividend reinvestment, shares			4,832
Treasury shares acquired	(14,180)					(14,180)
Treasury shares acquired, shares			(409,340)
Stock options exercised	251			(78)		329
Stock options exercised, shares			10,225
Stock compensation expense	1,727			1,727
Deferred benefits for directors- net	4			14				(10)
Ending Balance at Sep. 30, 2022	2,395,652	144,484	$ 141,834	1,634,280	1,048,532	(305,033)	(266,640)	(1,805)
Ending Balance, shares at Sep. 30, 2022			59,304,505
Beginning Balance at Dec. 31, 2022	2,426,662	144,484	$ 141,834	1,635,877	1,077,675	(308,964)	(262,416)	(1,828)
Beginning Balance, shares at Dec. 31, 2022			59,198,963
Net income	124,064				124,064
Other comprehensive loss	(35,490)						(35,490)
Comprehensive income (loss)	88,574
Common dividends declared	(61,729)				(61,729)
Preferred dividends declared	(7,594)				(7,594)
Stock issued for dividend reinvestment					(819)	819
Stock issued for dividend reinvestment, shares			22,455
Treasury shares acquired	(3,745)					(3,745)
Treasury shares acquired, shares			(162,432)
Stock options exercised	146			(60)		206
Stock options exercised, shares			6,432
Restricted stock granted				(8,260)		8,260
Restricted stock granted, shares			299,278
Stock compensation expense	5,806			5,806
Deferred benefits for directors- net	(179)			32				(211)
Ending Balance at Sep. 30, 2023	2,447,941	144,484	$ 141,834	1,633,395	1,131,597	(303,424)	(297,906)	(2,039)
Ending Balance, shares at Sep. 30, 2023			59,364,696
Beginning Balance at Jun. 30, 2023	2,464,998	144,484	$ 141,834	1,630,963	1,118,135	(303,770)	(264,627)	(2,021)
Beginning Balance, shares at Jun. 30, 2023			59,355,062
Net income	36,842				36,842
Other comprehensive loss	(33,279)						(33,279)
Comprehensive income (loss)	3,563
Common dividends declared	(20,583)				(20,583)
Preferred dividends declared	(2,531)				(2,531)
Stock issued for dividend reinvestment					(266)	266
Stock issued for dividend reinvestment, shares			7,275
Stock options exercised	24			(14)		38
Stock options exercised, shares			941
Restricted stock granted				(42)		42
Restricted stock granted, shares			1,418
Stock compensation expense	2,472			2,472
Deferred benefits for directors- net	(2)			16				(18)
Ending Balance at Sep. 30, 2023	$ 2,447,941	$ 144,484	$ 141,834	$ 1,633,395	$ 1,131,597	$ (303,424)	$ (297,906)	$ (2,039)
Ending Balance, shares at Sep. 30, 2023			59,364,696