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	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 592,096	$ 1,198,066
Percent of total loan class at period end	0.45%	0.91%
Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 583,043	$ 1,167,728
Interest Rate Reduction [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		515
Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	9,053	29,823
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 40,262	$ 95,623
Percent of total loan class at period end	0.09%	0.21%
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	$ 39,058	$ 93,583
Commercial, Financial, Leasing, etc. [Member] | Interest Rate Reduction [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		381
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	1,204	1,659
Commercial Real Estate [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 279,454	$ 454,445
Percent of total loan class at period end	0.78%	1.27%
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	$ 273,201	$ 440,195
Commercial Real Estate [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	6,253	14,250
Residential Builder and Developer [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		$ 70,683
Percent of total loan class at period end		6.42%
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		$ 70,683
Other Commercial Construction [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 215,598	$ 439,921
Percent of total loan class at period end	3.20%	6.54%
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	$ 215,598	$ 431,668
Other Commercial Construction [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		8,253
Residential [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 54,685	$ 125,157
Percent of total loan class at period end	0.24%	0.56%
Residential [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 53,239	$ 120,632
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	1,446	4,525
Residential Limited Documentation [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 1,721	$ 10,670
Percent of total loan class at period end	0.18%	1.11%
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	$ 1,721	$ 9,971
Residential Limited Documentation [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		699
Home Equity Lines and Loans [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 275	$ 1,053
Percent of total loan class at period end	0.01%	0.02%
Home Equity Lines and Loans [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 125	$ 482
Home Equity Lines and Loans [Member] | Interest Rate Reduction [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		134
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	150	437
Recreational Finance [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	40	240
Recreational Finance [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	40	240
Automobile [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	61	$ 274
Percent of total loan class at period end		0.01%
Automobile [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 61	$ 274