Loans and Leases and the Allowance for Credit Losses - Loan Modification Activities that were Considered Troubled Debt Restructurings (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) Modification
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	935
Pre-modification Recorded Investment	$ 61,456
Loans and leases, net of unearned discount	$ 62,294
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	37
Pre-modification Recorded Investment	$ 10,003
Loans and leases, net of unearned discount	$ 9,754
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	17
Pre-modification Recorded Investment	$ 7,582
Loans and leases, net of unearned discount	$ 7,332
Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	97
Pre-modification Recorded Investment	$ 24,051
Loans and leases, net of unearned discount	$ 25,404
Residential Limited Documentation [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	5
Pre-modification Recorded Investment	$ 1,076
Loans and leases, net of unearned discount	$ 1,087
Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	35
Pre-modification Recorded Investment	$ 2,150
Loans and leases, net of unearned discount	$ 2,160
Recreational Finance [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	177
Pre-modification Recorded Investment	$ 5,997
Loans and leases, net of unearned discount	$ 5,990
Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	534
Pre-modification Recorded Investment	$ 10,263
Loans and leases, net of unearned discount	$ 10,233
Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	33
Pre-modification Recorded Investment	$ 334
Loans and leases, net of unearned discount	334
Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	46,178
Principal Deferral [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	6,920
Principal Deferral [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	4,376
Principal Deferral [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	15,443
Principal Deferral [Member] | Residential Limited Documentation [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	894
Principal Deferral [Member] | Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	1,988
Principal Deferral [Member] | Recreational Finance [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	5,990
Principal Deferral [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	10,233
Principal Deferral [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	334
Other [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	2,155
Other [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	54
Other [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	2,101
Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	13,961
Combination of Concession Types [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	2,780
Combination of Concession Types [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	855
Combination of Concession Types [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	9,961
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	$ 172