Loans and Leases and the Allowance for Credit Losses - Summary of Current, Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	$ 1,748,497	$ 1,779,054
Accruing Loans Past Due 90 Days or More	354,029	491,018
Nonaccrual	2,341,938	2,438,435
Loans and leases, net of unearned discount	132,354,685	131,564,163
Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	127,910,221	126,855,656
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	252,987	448,462
Accruing Loans Past Due 90 Days or More	21,064	72,502
Nonaccrual	485,420	347,204
Loans and leases, net of unearned discount	45,058,033	41,850,566
Commercial, Financial, Leasing, etc. [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	44,298,562	40,982,398
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	424,005	311,188
Accruing Loans Past Due 90 Days or More	65,426	67,696
Nonaccrual	1,236,087	1,396,662
Loans and leases, net of unearned discount	35,743,775	36,748,173
Commercial [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	34,018,257	34,972,627
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	6,786	8,703
Nonaccrual	3,353	1,229
Loans and leases, net of unearned discount	1,100,494	1,314,730
Residential Builder and Developer [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,090,355	1,304,798
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	221,532	239,521
Accruing Loans Past Due 90 Days or More		549
Nonaccrual	136,004	124,937
Loans and leases, net of unearned discount	6,729,329	7,301,668
Other Commercial Construction [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,371,793	6,936,661
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	645,696	595,897
Accruing Loans Past Due 90 Days or More	261,290	345,402
Nonaccrual	240,753	272,090
Loans and leases, net of unearned discount	22,490,285	22,704,895
Residential [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	21,342,546	21,491,506
Residential Limited Documentation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	29,747	22,456
Nonaccrual	62,250	77,814
Loans and leases, net of unearned discount	957,985	1,051,052
Residential Limited Documentation [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	865,988	950,782
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	36,014	30,787
Nonaccrual	78,316	84,788
Loans and leases, net of unearned discount	4,692,711	5,006,886
Home Equity Lines and Loans [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,578,381	4,891,311
Recreational Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	67,149	54,593
Nonaccrual	30,524	44,630
Loans and leases, net of unearned discount	9,546,131	9,073,394
Recreational Finance [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	9,448,458	8,974,171
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	46,257	44,486
Nonaccrual	15,959	39,584
Loans and leases, net of unearned discount	3,917,794	4,477,276
Automobile [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,855,578	4,393,206
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	18,324	22,961
Accruing Loans Past Due 90 Days or More	6,249	4,869
Nonaccrual	53,272	49,497
Loans and leases, net of unearned discount	2,118,148	2,035,523
Other [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 2,040,303	$ 1,958,196