Loans and Leases and the Allowance for Credit Losses - Loan Modification Activities to Borrowers Experiencing Financial Difficulty on Financing Receivables (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 517,000	$ 638,000
Percent of Total Loan Class	0.38%	0.47%
Guaranteed by Government-Related Entities
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 36,000	$ 44,000
Commercial and industrial
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 111,000	$ 184,000
Percent of Total Loan Class	0.18%	0.32%
Commercial | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 131,000	$ 270,000
Percent of Total Loan Class	0.65%	1.07%
Residential builder and developer | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 0	$ 2,000
Percent of Total Loan Class	0.00%	0.18%
Other commercial construction | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 225,000	$ 131,000
Percent of Total Loan Class	4.53%	2.11%
Residential | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 50,000	$ 51,000
Percent of Total Loan Class	0.22%	0.22%
Home equity lines and loans | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 0	$ 0
Percent of Total Loan Class	0.00%	0.00%
Recreational finance | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 0	$ 0
Percent of Total Loan Class	0.00%	0.00%
Automobile | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 0	$ 0
Percent of Total Loan Class	0.00%	0.00%
Other | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 0	$ 0
Percent of Total Loan Class	0.00%	0.00%
Unfunded Loan Commitment
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 9,000	$ 29,000
Term Extension
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	431,000	584,000
Term Extension | Commercial and industrial
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	35,000	139,000
Term Extension | Commercial | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	131,000	267,000
Term Extension | Residential builder and developer | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	2,000
Term Extension | Other commercial construction | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	225,000	131,000
Term Extension | Residential | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	40,000	45,000
Term Extension | Home equity lines and loans | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Term Extension | Recreational finance | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Term Extension | Automobile | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Term Extension | Other | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Other (a)
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	5,000	50,000
Other (a) | Commercial and industrial
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	2,000	45,000
Other (a) | Commercial | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Other (a) | Residential builder and developer | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Other (a) | Other commercial construction | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Other (a) | Residential | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	3,000	5,000
Other (a) | Home equity lines and loans | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Other (a) | Recreational finance | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Other (a) | Automobile | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Other (a) | Other | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Combination of Modification Types
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	81,000	4,000
Combination of Modification Types | Commercial and industrial
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	74,000	0
Combination of Modification Types | Commercial | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	3,000
Combination of Modification Types | Residential builder and developer | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Combination of Modification Types | Other commercial construction | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Combination of Modification Types | Residential | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	7,000	1,000
Combination of Modification Types | Home equity lines and loans | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Combination of Modification Types | Recreational finance | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Combination of Modification Types | Automobile | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0
Combination of Modification Types | Other | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 0	$ 0