Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Surplus	Accumulated Other Comprehensive Income (Loss)	Undivided Profits
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	25,588			(6,800)	32,388
Stock issued for employee stock purchase plan	836		836
Stock-based compensation plans, net	2,948	2	2,946
Dividends on common stock	(26,759)				(26,759)
Ending balance at Mar. 31, 2025	3,531,485	1,259	2,515,372	(367,710)	1,382,564
Beginning balance at Dec. 31, 2025	3,419,240	1,448	2,846,581	(293,130)	864,341
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive (loss) income	47,309			(21,235)	68,544
Stock issued for employee stock purchase plan	838		838
Stock-based compensation plans, net	1,536	3	1,533
Dividends on common stock	(31,189)				(31,189)
Ending balance at Mar. 31, 2026	$ 3,437,734	$ 1,451	$ 2,848,952	$ (314,365)	$ 901,696