Allowance for Credit Losses (Summary of the Post-Modification Balance of Loans Experiencing Financial Difficulties) (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2023
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 5,063	$ 45,792
Percentage of Total Class of Loan	0.00%	0.10%
Extension of Term
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 143	$ 4,007
Duration of term	43 months	36 months
Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 0	$ 1,319
Reduction of interest rate	2.07%	2.23%
Delay in Contractual Payments
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 0	$ 35,304
Duration of term		17 months
Extended of Term and Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	4,920	$ 5,162
Commercial \| Commercial, industrial and other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 423	$ 37,897
Percentage of Total Class of Loan	0.00%	0.30%
Commercial \| Commercial, industrial and other \| Extension of Term
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 0	$ 1,938
Commercial \| Commercial, industrial and other \| Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0	221
Commercial \| Commercial, industrial and other \| Delay in Contractual Payments
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0	35,265
Commercial \| Commercial, industrial and other \| Extended of Term and Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	423	473
Commercial real estate \| Non-construction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 4,376	$ 5,709
Percentage of Total Class of Loan	0.00%	0.10%
Commercial real estate \| Non-construction \| Extension of Term
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 0	$ 467
Commercial real estate \| Non-construction \| Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0	827
Commercial real estate \| Non-construction \| Delay in Contractual Payments
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0	39
Commercial real estate \| Non-construction \| Extended of Term and Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	4,376	4,376
Home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 0	$ 203
Percentage of Total Class of Loan	0.00%	0.10%
Home equity \| Extension of Term
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 0	$ 203
Home equity \| Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0	0
Home equity \| Delay in Contractual Payments
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0	0
Home equity \| Extended of Term and Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0	0
Residential real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 264	$ 1,972
Percentage of Total Class of Loan	0.00%	0.10%
Residential real estate \| Extension of Term
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 143	$ 1,396
Residential real estate \| Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0	271
Residential real estate \| Delay in Contractual Payments
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0	0
Residential real estate \| Extended of Term and Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	121	305
Premium finance receivables \| Property and casualty insurance loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 0	$ 11
Percentage of Total Class of Loan	0.00%	0.00%
Premium finance receivables \| Property and casualty insurance loans \| Extension of Term
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 0	$ 3
Premium finance receivables \| Property and casualty insurance loans \| Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0	0
Premium finance receivables \| Property and casualty insurance loans \| Delay in Contractual Payments
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0	0
Premium finance receivables \| Property and casualty insurance loans \| Extended of Term and Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 0	$ 8

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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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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