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	143,704				143,704
Other comprehensive income (loss)	(18,773)						(18,773)
Comprehensive income (loss)	124,931
Common dividends declared	(43,961)				(43,961)
Preferred dividends declared	(5,063)				(5,063)
Stock issued for dividend reinvestment					(391)	391
Stock issued for dividend reinvestment, shares			11,720
Treasury shares acquired	(56,660)			191		(56,851)
Treasury shares acquired, shares			(1,510,576)
Stock options exercised	2,283			(858)		3,141
Stock options exercised, shares			91,643
Restricted stock granted				(4,272)		4,272
Restricted stock granted, shares			122,656
Stock compensation expense	2,580			2,580
Deferred benefits for directors- net	(11)			4				(15)
Ending Balance at Jun. 30, 2021	2,780,836	144,484	$ 141,834	1,632,460	925,977	(74,996)	12,586	(1,509)
Ending Balance, shares at Jun. 30, 2021			65,970,149
Beginning Balance at Mar. 31, 2021	2,785,522	144,484	$ 141,834	1,636,103	879,786	(24,989)	9,803	(1,499)
Beginning Balance, shares at Mar. 31, 2021			67,282,134
Net income	70,588				70,588
Other comprehensive income (loss)	2,783						2,783
Comprehensive income (loss)	73,371
Common dividends declared	(21,866)				(21,866)
Preferred dividends declared	(2,531)				(2,531)
Treasury shares acquired	(56,661)			7		(56,668)
Treasury shares acquired, shares			(1,505,441)
Stock options exercised	1,715			(674)		2,389
Stock options exercised, shares			70,800
Restricted stock granted				(4,272)		4,272
Restricted stock granted, shares			122,656
Stock compensation expense	1,292			1,292
Deferred benefits for directors- net	(6)			4				(10)
Ending Balance at Jun. 30, 2021	2,780,836	144,484	$ 141,834	1,632,460	925,977	(74,996)	12,586	(1,509)
Ending Balance, shares at Jun. 30, 2021			65,970,149
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	86,870				86,870
Other comprehensive income (loss)	(170,941)						(170,941)
Comprehensive income (loss)	(84,071)
Common dividends declared	(40,726)				(40,726)
Preferred dividends declared	(5,063)				(5,063)
Stock issued for dividend reinvestment					(637)	637
Stock issued for dividend reinvestment, shares			18,646
Treasury shares acquired	(99,420)					(99,420)
Treasury shares acquired, shares			(2,841,043)
Stock options exercised	1,378			(306)		1,684
Stock options exercised, shares			49,734
Restricted stock granted				(5,521)		5,521
Restricted stock granted, shares			164,206
Stock compensation expense	2,792			2,792
Deferred benefits for directors- net	(105)			10				(115)
Ending Balance at Jun. 30, 2022	2,467,951	144,484	$ 141,834	1,632,617	1,018,209	(291,337)	(176,061)	(1,795)
Ending Balance, shares at Jun. 30, 2022			59,698,788
Beginning Balance at Mar. 31, 2022	2,547,316	144,484	$ 141,834	1,636,705	998,315	(261,012)	(111,312)	(1,698)
Beginning Balance, shares at Mar. 31, 2022			60,613,414
Net income	42,748				42,748
Other comprehensive income (loss)	(64,749)						(64,749)
Comprehensive income (loss)	(22,001)
Common dividends declared	(20,191)				(20,191)
Preferred dividends declared	(2,531)				(2,531)
Stock issued for dividend reinvestment					(132)	132
Stock issued for dividend reinvestment, shares			4,115
Treasury shares acquired	(37,096)					(37,096)
Treasury shares acquired, shares			(1,116,472)
Stock options exercised	1,004			(114)		1,118
Stock options exercised, shares			33,525
Restricted stock granted				(5,521)		5,521
Restricted stock granted, shares			164,206
Stock compensation expense	1,551			1,551
Deferred benefits for directors- net	(101)			(4)				(97)
Ending Balance at Jun. 30, 2022	$ 2,467,951	$ 144,484	$ 141,834	$ 1,632,617	$ 1,018,209	$ (291,337)	$ (176,061)	$ (1,795)
Ending Balance, shares at Jun. 30, 2022			59,698,788