Loans and Leases and the Allowance for Credit Losses - Loan Modification Activities that were Considered Troubled Debt Restructurings (Detail) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2022 USD ($) Modification	Sep. 30, 2022 USD ($) Modification
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	839	2,691
Pre-modification Recorded Investment	$ 88,700	$ 227,509
Loans and leases, net of unearned discount	$ 89,800	$ 231,516
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	70	147
Pre-modification Recorded Investment	$ 32,451	$ 79,437
Loans and leases, net of unearned discount	$ 33,431	$ 81,371
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	14	44
Pre-modification Recorded Investment	$ 22,951	$ 33,349
Loans and leases, net of unearned discount	$ 22,887	$ 33,003
Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	57	221
Pre-modification Recorded Investment	$ 14,380	$ 56,912
Loans and leases, net of unearned discount	$ 14,564	$ 59,290
Residential Limited Documentation [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	2	7
Pre-modification Recorded Investment	$ 155	$ 1,231
Loans and leases, net of unearned discount	$ 155	$ 1,242
Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	25	93
Pre-modification Recorded Investment	$ 1,700	$ 6,483
Loans and leases, net of unearned discount	$ 1,700	$ 6,550
Recreational Finance [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	167	514
Pre-modification Recorded Investment	$ 6,937	$ 19,138
Loans and leases, net of unearned discount	$ 6,937	$ 19,131
Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	474	1,537
Pre-modification Recorded Investment	$ 9,755	$ 29,789
Loans and leases, net of unearned discount	$ 9,755	$ 29,759
Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	30	128
Pre-modification Recorded Investment	$ 371	$ 1,170
Loans and leases, net of unearned discount	371	1,170
Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	48,275	160,742
Principal Deferral [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	11,237	49,671
Principal Deferral [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	7,222	13,052
Principal Deferral [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	11,094	40,821
Principal Deferral [Member] | Residential Limited Documentation [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	155	1,049
Principal Deferral [Member] | Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	1,504	6,089
Principal Deferral [Member] | Recreational Finance [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	6,937	19,131
Principal Deferral [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	9,755	29,759
Principal Deferral [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	371	1,170
Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	446	455
Interest Rate Reduction [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	446	455
Other [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	351	3,206
Other [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	229	983
Other [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	122	2,223
Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	40,728	67,113
Combination of Concession Types [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	21,519	30,262
Combination of Concession Types [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	15,543	17,728
Combination of Concession Types [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	3,470	18,469
Combination of Concession Types [Member] | Residential Limited Documentation [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount		193
Combination of Concession Types [Member] | Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	$ 196	$ 461