Revenue from Contracts with Customers - Revenue from External Customers by Products and Services (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Revenue from External Customer [Line Items]
Total noninterest income in-scope of ASC 606	$ 47,403	$ 45,218	$ 96,605	$ 93,915
Total noninterest income (loss) out-of-scope of ASC 606	6,428	(3,341)	(321,104)	(5,623)
Total noninterest income (loss)	53,831	41,877	(224,499)	88,292
Insurance commissions
Revenue from External Customer [Line Items]
Total noninterest income in-scope of ASC 606	27,609	24,682	59,112	53,395
Service charges on deposit accounts
Revenue from External Customer [Line Items]
Total noninterest income in-scope of ASC 606	7,242	8,313	13,714	16,850
Trust and investment advisory fees
Revenue from External Customer [Line Items]
Total noninterest income in-scope of ASC 606	6,131	5,994	11,901	12,135
Debit card processing fees
Revenue from External Customer [Line Items]
Total noninterest income in-scope of ASC 606	3,513	3,223	6,683	6,168
Other noninterest income
Revenue from External Customer [Line Items]
Total noninterest income in-scope of ASC 606	$ 2,908	$ 3,006	$ 5,195	$ 5,367