Loans and Leases and the Allowance for Credit Losses - Loan Modification Activities to Borrowers Experiencing Financial Difficulty on Financing Receivables (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 304,231	[1]
Percent of total loan class	0.23%
Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 301,540
Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	2,691	[2]
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 43,850	[1]
Percent of total loan class	0.10%
Commercial, Financial, Leasing, etc. [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 43,564
Commercial, Financial, Leasing, etc. [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	286	[2]
Commercial Real Estate [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 120,304	[1]
Percent of total loan class	0.32%
Commercial Real Estate [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 120,304
Residential Builder and Developer [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 7,983	[1]
Percent of total loan class	0.64%
Residential Builder and Developer [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 7,983
Other Commercial Construction [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 91,811	[1]
Percent of total loan class	1.39%
Other Commercial Construction [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 91,811
Residential [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 34,423	[1]
Percent of total loan class	0.15%
Residential [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 32,460
Residential [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	1,963	[2]
Residential Limited Documentation [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 5,237	[1]
Percent of total loan class	0.51%
Residential Limited Documentation [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 5,237
Home Equity Lines and Loans [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 442	[1]
Percent of total loan class	0.01%
Home Equity Lines and Loans [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 442	[2]
Recreational Finance [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 136	[1]
Percent of total loan class	0.00%
Recreational Finance [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 136
Automobile [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 45	[1]
Percent of total loan class	0.00%
Automobile [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 45

[1] Includes approximately $23 million of loans guaranteed by government-related entities (predominantly first lien residential mortgage loans).

[2] Predominantly payment deferrals combined with interest rate reductions.