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, 2022	$ 1,265,737	$ 1,427	$ 677,593	$ 1,121,945	$ (11,035)	$ 11,035	$ (535,228)
Beginning Balance, Shares at Dec. 31, 2022		142,657,871
Treasury Stock, Beginning Balance, Shares at Dec. 31, 2022					(929,210)
Net earnings (Unaudited)	52,568			52,568
Stock option exercises (unaudited)	884		884
Stock option exercises, Shares		45,660
Cash dividends declared	(24,267)			(24,267)
Change in unrealized gain (loss) in investment securities available-for-sale, net of related income taxes (unaudited)	76,979						76,979
Shares purchased in connection with directors' deferred compensation plan, net (unaudited)					$ (236)	236
Shares purchased in connection with directors' deferred compensation plan, net (unaudited), Shares					1,421
Stock- based compensation expense (unaudited)	952		952
Ending Balance at Mar. 31, 2023	$ 1,372,853	$ 1,427	679,429	1,150,246	$ (11,271)	11,271	(458,249)
Ending Balance, Shares at Mar. 31, 2023		142,703,531
Treasury Stock, Ending Balance, Shares at Mar. 31, 2023	(927,789)				(927,789)
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)				(930,152)
Net earnings (Unaudited)	$ 53,397			53,397
Stock option exercises (unaudited)	1,623		1,622
Stock option exercises, 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)