Allowance for Credit Losses (Summary of the Post-Modification Balance of Loans Experiencing Financial Difficulties) (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 40,729
Percentage of Total Class of Loan	0.10%
Extension of Term
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 3,864
Duration of extension and delayed payment terms	27 months
Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 1,319
Reduction of interest rate	2.75%
Delay in Contractual Payments
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 35,304
Duration of extension and delayed payment terms	17 months
Extended of Term and Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 242
Commercial | Commercial, industrial and other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 37,474
Percentage of Total Class of Loan	0.30%
Commercial | Commercial, industrial and other | Extension of Term
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 1,938
Commercial | Commercial, industrial and other | Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	221
Commercial | Commercial, industrial and other | Delay in Contractual Payments
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	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	50
Commercial real estate | Non-construction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 1,333
Percentage of Total Class of Loan	0.00%
Commercial real estate | Non-construction | Extension of Term
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 467
Commercial real estate | Non-construction | Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	827
Commercial real estate | Non-construction | Delay in Contractual Payments
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	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	0
Home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 203
Percentage of Total Class of Loan	0.10%
Home equity | Extension of Term
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 203
Home equity | Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0
Home equity | Delay in Contractual Payments
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0
Home equity | Extended of Term and Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0
Residential real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 1,708
Percentage of Total Class of Loan	0.10%
Residential real estate | Extension of Term
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 1,253
Residential real estate | Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	271
Residential real estate | Delay in Contractual Payments
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	0
Residential real estate | Extended of Term and Reduction of Interest Rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	184
Premium finance receivables | Property and casualty insurance loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 11
Percentage of Total Class of Loan	0.00%
Premium finance receivables | Property and casualty insurance loans | Extension of Term
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	$ 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
Premium finance receivables | Property and casualty insurance loans | Delay in Contractual Payments
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification loan balances	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	$ 8