Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Deferred Compensation [Member]	Accumulated Other Comprehensive Earnings (Loss) [Member]
Beginning Balance at Dec. 31, 2023	$ 1,498,900	$ 1,427	$ 681,246	$ 1,219,525	$ (11,855)	$ 11,855	$ (403,298)
Beginning Balance, Shares at Dec. 31, 2023		142,716,939
Treasury Stock, Beginning Balance, Shares at Dec. 31, 2023					(930,152)
Net Income (Loss)	53,397			53,397
Stock option exercises/ stock unit conversions/ restricted stock activity (unaudited)	1,623	$ 1	1,622
Stock option exercises/ stock unit conversions/ restricted stock activity (unaudited), Shares		100,220
Cash dividends declared	(25,753)			(25,753)
Change in unrealized gain (loss) in investment securities available-for-sale, net of related income taxes (unaudited)	(37,929)						(37,929)
Shares purchased in connection with directors' deferred compensation plan, net (unaudited)					$ (265)	265
Shares purchased in connection with directors' deferred compensation plan, net (unaudited), Shares					(1,275)
Stock- based compensation expense (unaudited)	1,129		1,129
Ending Balance at Mar. 31, 2024	$ 1,491,367	$ 1,428	683,997	1,247,169	$ (12,120)	12,120	(441,227)
Ending Balance, Shares at Mar. 31, 2024		142,817,159
Treasury Stock, Ending Balance, Shares at Mar. 31, 2024	(931,427)				(931,427)
Beginning Balance at Dec. 31, 2024	$ 1,606,560	$ 1,429	689,338	1,340,082	$ (12,905)	12,905	(424,289)
Beginning Balance, Shares at Dec. 31, 2024		142,944,704
Treasury Stock, Beginning Balance, Shares at Dec. 31, 2024	(929,735)				(929,735)
Net Income (Loss)	$ 61,346			61,346
Stock option exercises/ stock unit conversions/ restricted stock activity (unaudited)	804	$ 1	803
Stock option exercises/ stock unit conversions/ restricted stock activity (unaudited), Shares		74,729
Cash dividends declared	(25,776)			(25,776)
Change in unrealized gain (loss) in investment securities available-for-sale, net of related income taxes (unaudited)	35,400						35,400
Shares purchased in connection with directors' deferred compensation plan, net (unaudited)					$ (358)	358
Shares purchased in connection with directors' deferred compensation plan, net (unaudited), Shares					1,382
Stock- based compensation expense (unaudited)	$ 1,927		1,927
Shares repurchased under stock repurchase authorization (unaudited), Shares	0
Ending Balance at Mar. 31, 2025	$ 1,680,261	$ 1,430	$ 692,068	$ 1,375,652	$ (13,263)	$ 13,263	$ (388,889)
Ending Balance, Shares at Mar. 31, 2025		143,019,433
Treasury Stock, Ending Balance, Shares at Mar. 31, 2025	(928,353)				(928,353)