Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Treasury Stock, Common [Member]	Deferred Compensation [Member]	Accumulated Other Total Comprehensive Earnings, net [Member]
Beginning Balance at Dec. 31, 2021	$ 1,759,224	$ 1,425	$ 676,871	$ 981,675	$ (10,090)	$ 10,090	$ 99,253
Beginning Balance, Shares at Dec. 31, 2021		142,532,116
Treasury Stock, Beginning Balance, Shares at Dec. 31, 2021					(936,897)
Net Income (Loss)	234,475			234,475
Stock option exercises/stock unit conversions/restricted stock activity	6,215	$ 4	6,211
Stock option exercises/stock unit conversions/restricted stock activity, Shares		370,314
Cash dividends declared	(94,205)			(94,205)
Change in unrealized gain (loss) in investment securities available-for-sale, net of related income taxes	(634,481)						(634,481)
Shares purchased in connection with directors’ deferred compensation plan, net					$ (945)	945
Shares purchased in connection with directors’ deferred compensation plan, net, Shares					7,687
Stock-based compensation expense	3,958		3,958
Shares repurchased and retired under stock repurchase authorization	(9,449)	$ (2)	(9,447)
Shares repurchased and retired under stock repurchase authorization, shares		(244,559)
Ending Balance at Dec. 31, 2022	1,265,737	$ 1,427	677,593	1,121,945	$ (11,035)	11,035	(535,228)
Ending Balance, Shares at Dec. 31, 2022		142,657,871
Treasury Stock, Ending Balance, Shares at Dec. 31, 2022					(929,210)
Net Income (Loss)	198,977			198,977
Stock option exercises/stock unit conversions/restricted stock activity	2,132	$ 1	2,131
Stock option exercises/stock unit conversions/restricted stock activity, Shares		160,405
Cash dividends declared	(101,397)			(101,397)
Change in unrealized gain (loss) in investment securities available-for-sale, net of related income taxes	131,930						131,930
Shares purchased in connection with directors’ deferred compensation plan, net					$ (820)	820
Shares purchased in connection with directors’ deferred compensation plan, net, Shares					(942)
Stock-based compensation expense	4,256		4,256
Shares repurchased and retired under stock repurchase authorization	(2,735)	$ (1)	(2,734)
Shares repurchased and retired under stock repurchase authorization, shares		(101,337)
Ending Balance at Dec. 31, 2023	$ 1,498,900	$ 1,427	681,246	1,219,525	$ (11,855)	11,855	(403,298)
Ending Balance, Shares at Dec. 31, 2023		142,716,939
Treasury Stock, Ending Balance, Shares at Dec. 31, 2023	930,152				(930,152)
Net Income (Loss)	$ 223,511			223,511
Stock option exercises/stock unit conversions/restricted stock activity	3,160	$ 2	3,158
Stock option exercises/stock unit conversions/restricted stock activity, Shares		227,765
Cash dividends declared	(102,954)			(102,954)
Change in unrealized gain (loss) in investment securities available-for-sale, net of related income taxes	(20,991)						(20,991)
Shares purchased in connection with directors’ deferred compensation plan, net					$ (1,050)	1,050
Shares purchased in connection with directors’ deferred compensation plan, net, Shares					417
Stock-based compensation expense	4,934		4,934
Ending Balance at Dec. 31, 2024	$ 1,606,560	$ 1,429	$ 689,338	$ 1,340,082	$ (12,905)	$ 12,905	$ (424,289)
Ending Balance, Shares at Dec. 31, 2024		142,944,704
Treasury Stock, Ending Balance, Shares at Dec. 31, 2024	929,735				(929,735)