Earnings Per Common Share (Basic and Diluted Earnings Per Common Share) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Earnings Per Share [Abstract]
Net income (loss)	$ 648,557	$ 582,542	$ 597,973
Less: Preferred stock dividends	6,675	6,675	6,675
Net income (loss) available to common shareholders	641,882	575,867	591,298
Less: Earnings allocated to participating securities	6,409	6,236	6,283
Net earnings allocated to common stock	635,473	569,631	585,015
Distributed earnings allocated to common stock	252,823	239,879	229,749
Undistributed earnings allocated to common stock	$ 382,650	$ 329,752	$ 355,266
Weighted-average shares outstanding for basic earnings per common share	64,054,228	64,120,455	64,204,239
Dilutive effect of stock compensation	45,010	142,191	200,594
Weighted-average shares outstanding for diluted earnings per common share	64,099,238	64,262,646	64,404,833