Earnings Per Common Share - Basic and Diluted Earnings Per Common Share (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Earnings Per Share [Abstract]
Net income	$ 180,209	$ 174,380	$ 523,255	$ 482,305
Less: Preferred stock dividends	1,668	1,668	5,006	5,006
Net income available to common shareholders	178,541	172,712	518,249	477,299
Less: Earnings allocated to participating securities	2,345	1,737	6,525	4,713
Distributed earnings allocated to common stock	63,977	64,025	191,116	189,402
Undistributed earnings allocated to common stock	112,219	106,950	320,608	283,184
Net earnings allocated to common stock	$ 176,196	$ 170,975	$ 511,724	$ 472,586
Weighted-average shares outstanding for basic earnings per common share	62,117,196	64,080,473	62,554,196	64,211,247
Dilutive effect of stock compensation	0	40,042	0	54,999
Weighted-average shares outstanding for diluted earnings per common share	62,117,196	64,120,515	62,554,196	64,266,246