Loans and Leases and the Allowance for Credit Losses - Summary of Current, Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	$ 1,891,910	$ 1,779,054
Accruing Loans Past Due 90 Days or More	407,457	491,018
Nonaccrual	2,556,799	2,438,435
Loans and leases, net of unearned discount	132,937,692	131,564,163
Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	128,081,526	126,855,656
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	489,322	448,462
Accruing Loans Past Due 90 Days or More	61,550	72,502
Nonaccrual	382,268	347,204
Loans and leases, net of unearned discount	43,758,361	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	42,825,221	40,982,398
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	399,114	311,188
Accruing Loans Past Due 90 Days or More	37,137	67,696
Nonaccrual	1,516,655	1,396,662
Loans and leases, net of unearned discount	37,202,925	36,748,173
Commercial [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	35,250,019	34,972,627
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	111,894	8,703
Nonaccrual	3,303	1,229
Loans and leases, net of unearned discount	1,241,890	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	1,126,693	1,304,798
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	242,226	239,521
Accruing Loans Past Due 90 Days or More	10,843	549
Nonaccrual	143,015	124,937
Loans and leases, net of unearned discount	6,627,726	7,301,668
Other Commercial Construction [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,231,642	6,936,661
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	496,225	595,897
Accruing Loans Past Due 90 Days or More	292,950	345,402
Nonaccrual	253,646	272,090
Loans and leases, net of unearned discount	22,769,784	22,704,895
Residential [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	21,726,963	21,491,506
Residential Limited Documentation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	26,046	22,456
Nonaccrual	68,935	77,814
Loans and leases, net of unearned discount	1,020,161	1,051,052
Residential Limited Documentation [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	925,180	950,782
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	26,679	30,787
Nonaccrual	80,766	84,788
Loans and leases, net of unearned discount	4,859,267	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	4,751,822	4,891,311
Recreational Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	48,448	54,593
Nonaccrual	34,186	44,630
Loans and leases, net of unearned discount	9,149,221	9,073,394
Recreational Finance [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	9,066,587	8,974,171
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	35,270	44,486
Nonaccrual	26,842	39,584
Loans and leases, net of unearned discount	4,311,147	4,477,276
Automobile [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,249,035	4,393,206
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	16,686	22,961
Accruing Loans Past Due 90 Days or More	4,977	4,869
Nonaccrual	47,183	49,497
Loans and leases, net of unearned discount	1,997,210	2,035,523
Other [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 1,928,364	$ 1,958,196