Earnings Per Common Share - Basic and Diluted Earnings Per Common Share (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net income	$ 107,975	$ 95,056	$ 342,058	$ 242,881
Less: Preferred stock dividends	1,668	0	5,488	2,016
Redemption of preferred stock	0	0	0	5,514
Net income available to common shareholders	106,307	95,056	336,570	235,351
Less: Earnings allocated to participating securities	932	877	3,228	2,236
Distributed earnings allocated to common stock	47,740	44,546	139,224	133,511
Undistributed earnings allocated to common stock	57,635	49,633	194,118	99,604
Net earnings allocated to common stock	$ 105,375	$ 94,179	$ 333,342	$ 233,115
Weighted-average shares outstanding for basic earnings per common share	63,652,020	62,726,542	63,522,884	62,655,393
Dilutive effect of stock compensation	444,636	193,116	489,219	263,028
Weighted-average shares outstanding for diluted earnings per common share	64,096,656	62,919,658	64,012,103	62,918,421