Loans and Leases and the Allowance for Credit Losses - Loan Modification Activities that were Considered Troubled Debt Restructurings (Detail) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2022 USD ($) Modification	Jun. 30, 2022 USD ($) Modification
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	917	1,852
Pre-modification Recorded Investment	$ 77,353	$ 138,809
Loans and leases, net of unearned discount	$ 79,422	$ 141,716
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	40	77
Pre-modification Recorded Investment	$ 36,983	$ 46,986
Loans and leases, net of unearned discount	$ 38,186	$ 47,940
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	13	30
Pre-modification Recorded Investment	$ 2,816	$ 10,398
Loans and leases, net of unearned discount	$ 2,784	$ 10,116
Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	67	164
Pre-modification Recorded Investment	$ 18,481	$ 42,532
Loans and leases, net of unearned discount	$ 19,322	$ 44,726
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	33	68
Pre-modification Recorded Investment	$ 2,633	$ 4,783
Loans and leases, net of unearned discount	$ 2,690	$ 4,850
Recreational Finance [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	170	347
Pre-modification Recorded Investment	$ 6,204	$ 12,201
Loans and leases, net of unearned discount	$ 6,204	$ 12,194
Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	529	1,063
Pre-modification Recorded Investment	$ 9,771	$ 20,034
Loans and leases, net of unearned discount	$ 9,771	$ 20,004
Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	65	98
Pre-modification Recorded Investment	$ 465	$ 799
Loans and leases, net of unearned discount	465	799
Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	66,289	112,467
Principal Deferral [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	31,514	38,434
Principal Deferral [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	1,454	5,830
Principal Deferral [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	14,284	29,727
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	2,597	4,585
Principal Deferral [Member] | Recreational Finance [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	6,204	12,194
Principal Deferral [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	9,771	20,004
Principal Deferral [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	465	799
Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	9	9
Interest Rate Reduction [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	9	9
Other [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	700	2,855
Other [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	700	754
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	12,424	26,385
Combination of Concession Types [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	5,963	8,743
Combination of Concession Types [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	1,330	2,185
Combination of Concession Types [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	5,038	14,999
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	$ 93	$ 265