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		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 441,000	$ 348,000	$ 916,000	$ 641,000
Percent of Total Loan Class	0.33%	0.26%	0.68%	0.48%
Commercial and industrial
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 64,000	$ 27,000	$ 209,000	$ 95,000
Percent of Total Loan Class	0.11%	0.05%	0.35%	0.17%
Commercial | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 168,000	$ 60,000	$ 377,000	$ 150,000
Percent of Total Loan Class	0.74%	0.22%	1.66%	0.56%
Residential builder and developer | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 26,000	$ 85,000	$ 27,000	$ 91,000
Percent of Total Loan Class	2.49%	7.49%	2.62%	7.99%
Other commercial construction | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 125,000	$ 132,000	$ 197,000	$ 223,000
Percent of Total Loan Class	2.18%	1.95%	3.44%	3.29%
Residential | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 56,000	$ 39,000	$ 101,000	$ 72,000
Percent of Total Loan Class	0.25%	0.17%	0.46%	0.32%
Residential — limited documentation | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 2,000	$ 4,000	$ 4,000	$ 9,000
Percent of Total Loan Class	0.26%	0.38%	0.45%	0.90%
Home equity lines and loans | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 0	$ 1,000	$ 1,000	$ 1,000
Percent of Total Loan Class	0.00%	0.02%	0.03%	0.02%
Recreational finance | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 0	$ 0	$ 0	$ 0
Percent of Total Loan Class	0.00%	0.00%	0.00%	0.00%
Automobile | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 0	$ 0	$ 0	$ 0
Percent of Total Loan Class	0.00%	0.00%	0.00%	0.01%
Other | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 0	$ 0	$ 0	$ 0
Percent of Total Loan Class	0.00%	0.00%	0.00%	0.00%
Payment Deferral (a)
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 427,000	$ 329,000	$ 896,000	$ 619,000
Payment Deferral (a) | Commercial and industrial
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	51,000	26,000	196,000	93,000
Payment Deferral (a) | Commercial | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	168,000	52,000	373,000	142,000
Payment Deferral (a) | Residential builder and developer | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	26,000	85,000	27,000	91,000
Payment Deferral (a) | Other commercial construction | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	125,000	124,000	197,000	215,000
Payment Deferral (a) | Residential | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	55,000	38,000	99,000	69,000
Payment Deferral (a) | Residential — limited documentation | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	2,000	3,000	4,000	8,000
Payment Deferral (a) | Home equity lines and loans | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	1,000	0	1,000
Payment Deferral (a) | Recreational finance | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Payment Deferral (a) | Automobile | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Payment Deferral (a) | Other | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Interest Rate Reduction
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	13,000	1,000	13,000	1,000
Interest Rate Reduction | Commercial and industrial
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	13,000	1,000	13,000	1,000
Interest Rate Reduction | Commercial | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Interest Rate Reduction | Residential builder and developer | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Interest Rate Reduction | Other commercial construction | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Interest Rate Reduction | Residential | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Interest Rate Reduction | Residential — limited documentation | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Interest Rate Reduction | Home equity lines and loans | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Interest Rate Reduction | Recreational finance | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Interest Rate Reduction | Automobile | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Interest Rate Reduction | Other | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Other
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Other | Commercial and industrial
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Other | Commercial | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Other | Residential builder and developer | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Other | Other commercial construction | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Other | Residential | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Other | Residential — limited documentation | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Other | Home equity lines and loans | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Other | Recreational finance | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Other | Automobile | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Other | Other | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Combination of Modification Types
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	1,000	18,000	7,000	21,000
Combination of Modification Types | Commercial and industrial
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	1,000
Combination of Modification Types | Commercial | Commercial Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	8,000	4,000	8,000
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	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	8,000	0	8,000
Combination of Modification Types | Residential | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	1,000	1,000	2,000	3,000
Combination of Modification Types | Residential — limited documentation | Residential Real Estate
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	1,000	0	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	1,000	0
Combination of Modification Types | Recreational finance | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Combination of Modification Types | Automobile | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	0	0	0	0
Combination of Modification Types | Other | Consumer:
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Modified in period	$ 0	$ 0	$ 0	$ 0