Revenue Recognition - Summary of Disaggregation of Revenue According to Revenue Stream and Business Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	$ 15,423	$ (442)
Noninterest income	204,793	166,198
Trust and Securities Processing [Member]
Disaggregation Of Revenue [Line Items]
Noninterest income	94,667	79,781
Trading and Investment Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	7,618	5,582
Noninterest income	7,740	5,911
Service Charges On Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	32	39
Noninterest income	29,474	27,457
Insurance Fees and Commissions [Member]
Disaggregation Of Revenue [Line Items]
Noninterest income	255	178
Brokerage Fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest income	21,089	18,102
Bankcard Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	(12,173)	(11,796)
Noninterest income	28,878	26,293
Investment Securities Gains (Losses), Net [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	3,046	(4,782)
Noninterest income	3,046	(4,782)
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue (Expense) out of Scope of ASC 606	16,900	10,515
Noninterest income	19,644	13,258
Commercial Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	44,242	40,570
Commercial Banking [Member] \| Trust and Securities Processing [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	761	479
Commercial Banking [Member] \| Service Charges On Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	16,144	14,581
Commercial Banking [Member] \| Brokerage Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	87	67
Commercial Banking [Member] \| Bankcard Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	26,086	24,164
Commercial Banking [Member] \| Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	1,164	1,279
Institutional Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	111,301	95,732
Institutional Banking [Member] \| Trust and Securities Processing [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	73,325	61,248
Institutional Banking [Member] \| Trading and Investment Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	122	329
Institutional Banking [Member] \| Service Charges On Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	10,857	10,859
Institutional Banking [Member] \| Brokerage Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	18,365	15,372
Institutional Banking [Member] \| Bankcard Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	7,894	7,242
Institutional Banking [Member] \| Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	738	682
Personal Banking [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	33,827	30,338
Personal Banking [Member] \| Trust and Securities Processing [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	20,581	18,054
Personal Banking [Member] \| Service Charges On Deposit Accounts [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	2,441	1,978
Personal Banking [Member] \| Insurance Fees and Commissions [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	255	178
Personal Banking [Member] \| Brokerage Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	2,637	2,663
Personal Banking [Member] \| Bankcard Fees [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	7,071	6,683
Personal Banking [Member] \| Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue Scope of ASC 606	$ 842	$ 782

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The total amount of noninterest income which may be derived from: (1) fees and commissions; (2) premiums earned; (3) insurance policy charges; (4) the sale or disposal of assets; and (5) other sources not otherwise specified.

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