Earnings Per Common Share - Basic and Diluted Earnings Per Common Share (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net income	$ 118,068	$ 93,072	$ 234,083	$ 147,825
Less: Preferred stock dividends	1,669	0	3,820	2,016
Redemption of preferred stock	0	0	0	5,514
Net income available to common shareholders	116,399	93,072	230,263	140,295
Less: Earnings allocated to participating securities	1,141	868	2,307	1,335
Distributed earnings allocated to common stock	45,824	44,453	91,484	88,965
Undistributed earnings allocated to common stock	69,434	47,751	136,472	49,995
Net earnings allocated to common stock	$ 115,258	$ 92,204	$ 227,956	$ 138,960
Weighted-average shares outstanding for basic earnings per common share	63,606,340	62,596,171	63,457,245	62,619,427
Dilutive effect of stock compensation	495,819	204,848	511,288	300,667
Weighted-average shares outstanding for diluted earnings per common share	64,102,159	62,801,019	63,968,533	62,920,094