Revenue Recognition - Summary of Disaggregation of Revenue According to Revenue Stream and Business Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	$ 24,085	$ 3,300
Noninterest income	159,244	130,200
Trust and Securities Processing [Member]
Disaggregation Of Revenue [Line Items]
Noninterest income	69,478	62,359
Trading and Investment Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	5,417	5,150
Noninterest income	5,462	5,308
Service Charges On Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	27	18
Noninterest income	20,757	21,159
Insurance Fees and Commissions [Member]
Disaggregation Of Revenue [Line Items]
Noninterest income	283	274
Brokerage Fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest income	13,160	13,676
Bankcard Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	(7,883)	(9,732)
Noninterest income	21,968	18,172
Investment Securities Gains (Losses), Net [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	9,371	(5,324)
Noninterest income	9,371	(5,324)
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	17,153	13,188
Noninterest income	18,765	14,576
Commercial Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	27,105	24,448
Noninterest income	42,966	22,902
Commercial Banking [Member] | Service Charges On Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	10,351	8,528
Commercial Banking [Member] | Brokerage Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	68	63
Commercial Banking [Member] | Bankcard Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	16,548	15,632
Commercial Banking [Member] | Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	138	225
Institutional Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	84,660	79,007
Noninterest income	92,716	84,238
Institutional Banking [Member] | Trust and Securities Processing [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	55,241	49,179
Institutional Banking [Member] | Trading and Investment Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	45	158
Institutional Banking [Member] | Service Charges On Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	9,095	10,738
Institutional Banking [Member] | Brokerage Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	11,323	11,795
Institutional Banking [Member] | Bankcard Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	8,157	6,679
Institutional Banking [Member] | Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	799	458
Personal Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	23,394	23,445
Noninterest income	23,562	23,060
Personal Banking [Member] | Trust and Securities Processing [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	14,237	13,180
Personal Banking [Member] | Service Charges On Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	1,284	1,875
Personal Banking [Member] | Insurance Fees and Commissions [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	283	274
Personal Banking [Member] | Brokerage Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	1,769	1,818
Personal Banking [Member] | Bankcard Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	5,146	5,593
Personal Banking [Member] | Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	$ 675	$ 705