Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Surplus	Accumulated Other Comprehensive Income (Loss)	Undivided Profits
Beginning balance at Dec. 31, 2023	$ 3,426,488	$ 1,252	$ 2,499,930	$ (404,375)	$ 1,329,681
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive (loss) income	78,528			(1,106)	79,634
Stock issued for employee stock purchase plan	970		970
Stock-based compensation plans, net	5,572	3	5,569
Dividends on common stock	(52,689)				(52,689)
Ending balance at Jun. 30, 2024	3,458,869	1,255	2,506,469	(405,481)	1,356,626
Beginning balance at Mar. 31, 2024	3,439,126	1,254	2,503,673	(408,016)	1,342,215
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive (loss) income	43,298			2,535	40,763
Stock-based compensation plans, net	2,797	1	2,796
Dividends on common stock	(26,352)				(26,352)
Ending balance at Jun. 30, 2024	3,458,869	1,255	2,506,469	(405,481)	1,356,626
Beginning balance at Dec. 31, 2024	3,528,872	1,257	2,511,590	(360,910)	1,376,935
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive (loss) income	67,171			(19,990)	87,161
Stock issued for employee stock purchase plan	836		836
Stock-based compensation plans, net	5,863	3	5,860
Dividends on common stock	(53,532)				(53,532)
Ending balance at Jun. 30, 2025	3,549,210	1,260	2,518,286	(380,900)	1,410,564
Beginning balance at Mar. 31, 2025	3,531,485	1,259	2,515,372	(367,710)	1,382,564
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive (loss) income	41,583			(13,190)	54,773
Stock-based compensation plans, net	2,915	1	2,914
Dividends on common stock	(26,773)				(26,773)
Ending balance at Jun. 30, 2025	$ 3,549,210	$ 1,260	$ 2,518,286	$ (380,900)	$ 1,410,564