Segment Information - Summary of Segment Reporting Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Net interest income	$ 234,320	$ 191,502
Provision for credit losses	6,890	(3,410)
Other income	32,744	46,025
Other expense	137,419	139,175
Income taxes	24,448	20,098
Net income (loss)	98,307	81,664
Total assets (liabilities)	30,182,241	29,365,511
Average assets (liabilities)	29,512,289	29,344,522
Operating Segments [Member] | Community Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	236,263	189,682
Provision for credit losses	6,890	(3,410)
Other income	24,170	24,901
Other expense	122,787	114,539
Income taxes	26,064	20,429
Net income (loss)	104,692	83,025
Total assets (liabilities)	29,815,781	29,030,100
Average assets (liabilities)	29,177,990	29,023,901
Operating Segments [Member] | Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	2,122	2,317
Provision for credit losses	0	0
Other income	10,861	23,397
Other expense	15,085	25,448
Income taxes	(424)	57
Net income (loss)	(1,678)	209
Total assets (liabilities)	458,632	589,503
Average assets (liabilities)	391,707	475,243
Other [Member]
Segment Reporting Information [Line Items]
Net interest income	5,310	2,125
Provision for credit losses	0	0
Other income	243	(60)
Other expense	832	(227)
Income taxes	(1,192)	(388)
Net income (loss)	(4,707)	(1,570)
Total assets (liabilities)	74,283	39,940
Average assets (liabilities)	51,224	33,357
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net interest income	1,245	1,628
Provision for credit losses	0	0
Other income	(2,530)	(2,213)
Other expense	(1,285)	(585)
Income taxes	0	0
Net income (loss)	0	0
Total assets (liabilities)	(166,455)	(294,032)
Average assets (liabilities)	$ (108,632)	$ (187,979)