Revenue from Contracts with Customers - Summary of Sources of Noninterest Income that are Subject to Revenue Recognition Accounting Guidance (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation Of Revenue [Line Items]
Brokerage services income	$ 20,190	$ 13,113
Other revenues from operations:
Total other income	540,887	505,598
Service Charges on Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contract with customer	101,507	92,777
Trust Income [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contract with customer	169,213	156,022
ASU 2014-09 [Member]
Disaggregation Of Revenue [Line Items]
Brokerage services income	20,190	13,113
Other revenues from operations:
Merchant discount and credit card fees	31,755	24,363
Other	24,779	22,910
Total other income	347,444	309,185
ASU 2014-09 [Member] | Service Charges on Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contract with customer	101,507	92,777
ASU 2014-09 [Member] | Trust Income [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contract with customer	169,213	156,022
ASU 2014-09 [Member] | Business Banking [Member]
Other revenues from operations:
Merchant discount and credit card fees	12,805	9,481
Total other income	27,486	21,978
ASU 2014-09 [Member] | Business Banking [Member] | Service Charges on Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contract with customer	14,681	12,497
ASU 2014-09 [Member] | Commercial Banking [Member]
Other revenues from operations:
Merchant discount and credit card fees	13,459	10,407
Other	1,903	958
Total other income	40,933	35,660
ASU 2014-09 [Member] | Commercial Banking [Member] | Service Charges on Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contract with customer	25,571	24,295
ASU 2014-09 [Member] | Commercial Real Estate [Member]
Other revenues from operations:
Merchant discount and credit card fees	874	445
Other	2,464	1,091
Total other income	6,816	4,429
ASU 2014-09 [Member] | Commercial Real Estate [Member] | Service Charges on Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contract with customer	3,478	2,893
ASU 2014-09 [Member] | Discretionary Portfolio [Member]
Other revenues from operations:
Other	693	384
Total other income	693	384
ASU 2014-09 [Member] | Residential Mortgage Banking [Member]
Other revenues from operations:
Other	1,729	1,722
Total other income	1,729	1,722
ASU 2014-09 [Member] | Retail Banking [Member]
Other revenues from operations:
Merchant discount and credit card fees	4,510	3,921
Other	5,099	5,807
Total other income	65,956	61,180
ASU 2014-09 [Member] | Retail Banking [Member] | Service Charges on Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contract with customer	56,347	51,452
ASU 2014-09 [Member] | All Other [Member]
Disaggregation Of Revenue [Line Items]
Brokerage services income	20,190	13,113
Other revenues from operations:
Merchant discount and credit card fees	107	109
Other	12,891	12,948
Total other income	203,831	183,832
ASU 2014-09 [Member] | All Other [Member] | Service Charges on Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contract with customer	1,430	1,640
ASU 2014-09 [Member] | All Other [Member] | Trust Income [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contract with customer	$ 169,213	$ 156,022