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, 2020	$ 2,756,737	$ 144,484	$ 141,834	$ 1,634,815	$ 831,688	$ (25,949)	$ 31,359	$ (1,494)
Beginning Balance, shares at Dec. 31, 2020			67,254,706
Net income	188,112				188,112
Other comprehensive income (loss)	(26,896)						(26,896)
Comprehensive income (loss)	161,216
Common dividends declared	(65,069)				(65,069)
Preferred dividends declared	(7,594)
Stock issued for dividend reinvestment					(391)	391
Stock issued for dividend reinvestment, shares			11,720
Treasury shares acquired	(128,006)			191		(128,197)
Treasury shares acquired, shares			(3,649,091)
Stock options exercised	2,300			(867)		3,167
Stock options exercised, shares			92,393
Restricted stock granted				(4,486)		4,486
Restricted stock granted, shares			128,821
Stock compensation expense	4,415			4,415
Deferred benefits for directors- net	(16)			18				(34)
Ending Balance at Sep. 30, 2021	2,723,983	144,484	$ 141,834	1,634,086	946,746	(146,102)	4,463	(1,528)
Ending Balance, shares at Sep. 30, 2021			63,838,549
Beginning Balance at Jun. 30, 2021	2,780,836	144,484	$ 141,834	1,632,460	925,977	(74,996)	12,586	(1,509)
Beginning Balance, shares at Jun. 30, 2021			65,970,149
Net income	44,408				44,408
Other comprehensive income (loss)	(8,123)						(8,123)
Comprehensive income (loss)	36,285
Common dividends declared	(21,108)				(21,108)
Preferred dividends declared	(2,531)				(2,531)
Treasury shares acquired	(71,346)					(71,346)
Treasury shares acquired, shares			(2,138,515)
Stock options exercised	16			(10)		26
Stock options exercised, shares			750
Restricted stock granted				(214)		214
Restricted stock granted, shares			6,165
Stock compensation expense	1,836			1,836
Deferred benefits for directors- net	(5)			14				(19)
Ending Balance at Sep. 30, 2021	2,723,983	144,484	$ 141,834	1,634,086	946,746	(146,102)	4,463	(1,528)
Ending Balance, shares at Sep. 30, 2021			63,838,549
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 income (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 income (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