Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balance at Dec. 31, 2023	$ 3,803,661	$ 309,513	$ 1,739,671	$ 2,375,604	$ (621,127)
Balance, Shares Issued at Dec. 31, 2023		92,947
Net income	108,612			108,612
Other comprehensive income (loss)	(32,388)				(32,388)
Comprehensive income	76,224
Cash dividends declared	(26,527)			(26,527)
Common stock activity, long-term incentive plans	(819)		(866)	47
Issuance of stock from dividend reinvestment and stock purchase plans	897		897
Balance at Mar. 31, 2024	3,853,436	$ 309,513	1,739,702	2,457,736	(653,515)
Balance, Shares Issued at Mar. 31, 2024		92,947
Balance at Dec. 31, 2024	$ 4,127,636	$ 309,513	1,719,609	2,704,606	(606,092)
Balance, Shares Issued at Dec. 31, 2024	92,947	92,947
Net income	$ 119,504			119,504
Other comprehensive income (loss)	91,120				91,120
Comprehensive income	210,624
Cash dividends declared	(39,460)			(39,460)
Common stock activity, long-term incentive plans	(464)		(471)	7
Issuance of stock from dividend reinvestment and stock purchase plans	1,083		1,083
Repurchase of common stock	(20,747)		(20,747)
Balance at Mar. 31, 2025	$ 4,278,672	$ 309,513	$ 1,699,474	$ 2,784,657	$ (514,972)
Balance, Shares Issued at Mar. 31, 2025	92,947	92,947