Loans and Leases and the Allowance for Credit Losses - Summary of loans in Accrual and Nonaccrual Status (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable Recorded Investment [Line Items]
Total Loans	$ 88,104,572	$ 89,043,040
30-89 Days Past Due	792,838	845,930
Accruing Loans Past Due 90 Days or More	776,751	963,399
Nonaccrual	2,134,231	2,060,083
Loans and leases, net of unearned discount	91,808,392	92,912,452
Residential [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	13,126,694	13,294,872
30-89 Days Past Due	249,731	239,561
Accruing Loans Past Due 90 Days or More	687,397	920,080
Nonaccrual	341,671	355,858
Loans and leases, net of unearned discount	14,405,493	14,810,371
Residential Limited Documentation [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,050,328	1,124,520
30-89 Days Past Due	16,546	16,666
Nonaccrual	123,512	122,888
Loans and leases, net of unearned discount	1,190,386	1,264,074
Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	3,407,958	3,476,617
30-89 Days Past Due	16,939	15,486
Nonaccrual	71,489	70,488
Loans and leases, net of unearned discount	3,496,386	3,562,591
Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	8,156,368	7,985,173
30-89 Days Past Due	33,093	40,544
Nonaccrual	31,546	27,811
Loans and leases, net of unearned discount	8,221,007	8,053,528
Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	4,688,513	4,604,772
30-89 Days Past Due	31,707	40,064
Nonaccrual	35,350	34,037
Loans and leases, net of unearned discount	4,755,570	4,678,873
Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,631,907	1,620,147
30-89 Days Past Due	10,305	12,223
Accruing Loans Past Due 90 Days or More	3,703	3,302
Nonaccrual	44,060	44,289
Loans and leases, net of unearned discount	1,689,975	1,679,961
Revolving Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases, net of unearned discount	16,769,547	16,234,904
Revolving Loans [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	2,558
Nonaccrual	516	263
Loans and leases, net of unearned discount	41,502	72,572
Revolving Loans [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	574	346
Nonaccrual	4,772	4,951
Loans and leases, net of unearned discount	2,254,454	2,353,576
Revolving Loans [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due		1,908
Nonaccrual	40,552	40,807
Loans and leases, net of unearned discount	1,198,617	1,190,811
Revolving Loans Converted to Term Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases, net of unearned discount	1,239,662	1,199,887
Revolving Loans Converted to Term Loans [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	15,430	14,421
Nonaccrual	61,257	59,787
Loans and leases, net of unearned discount	1,194,179	1,156,983
Revolving Loans Converted to Term Loans [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	373	434
Nonaccrual	104	129
Loans and leases, net of unearned discount	1,921	2,068
Current [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	13,126,694	13,294,872
Current [Member] | Residential Limited Documentation [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,050,328	1,124,520
Current [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	3,407,958	3,476,617
Current [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	8,156,368	7,985,173
Current [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	4,688,513	4,604,772
Current [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,631,907	1,620,147
Current [Member] | Revolving Loans [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	38,428	72,309
Current [Member] | Revolving Loans [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	2,249,108	2,348,279
Current [Member] | Revolving Loans [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,158,065	1,148,096
Current [Member] | Revolving Loans Converted to Term Loans [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,117,492	1,082,775
Current [Member] | Revolving Loans Converted to Term Loans [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,444	1,505
Term Loans 2022 [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases, net of unearned discount	4,600,284
Term Loans 2022 [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	3,136
Loans and leases, net of unearned discount	1,169,228
Term Loans 2022 [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases, net of unearned discount	70
Term Loans 2022 [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	88
Loans and leases, net of unearned discount	703,933
Term Loans 2022 [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	288
Loans and leases, net of unearned discount	567,885
Term Loans 2022 [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	2,187
Nonaccrual	1,538
Loans and leases, net of unearned discount	60,236
Term Loans 2022 [Member] | Current [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,166,092
Term Loans 2022 [Member] | Current [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	70
Term Loans 2022 [Member] | Current [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	703,845
Term Loans 2022 [Member] | Current [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	567,597
Term Loans 2022 [Member] | Current [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	56,511
Term Loans 2021 [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases, net of unearned discount	17,170,499	18,817,411
Term Loans 2021 [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	19,193	15,245
Accruing Loans Past Due 90 Days or More	28,249	10,924
Nonaccrual	5,764	3,359
Loans and leases, net of unearned discount	2,876,128	3,086,646
Term Loans 2021 [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Nonaccrual	15
Loans and leases, net of unearned discount	397	304
Term Loans 2021 [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	5,701	5,929
Nonaccrual	2,664	1,341
Loans and leases, net of unearned discount	2,728,040	2,897,381
Term Loans 2021 [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	7,968	8,508
Nonaccrual	3,756	1,588
Loans and leases, net of unearned discount	2,064,282	2,230,157
Term Loans 2021 [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	907	2,937
Nonaccrual	883	2,051
Loans and leases, net of unearned discount	224,736	249,334
Term Loans 2021 [Member] | Current [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	2,822,922	3,057,118
Term Loans 2021 [Member] | Current [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	382	304
Term Loans 2021 [Member] | Current [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	2,719,675	2,890,111
Term Loans 2021 [Member] | Current [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	2,052,558	2,220,061
Term Loans 2021 [Member] | Current [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	222,946	244,346
Term Loans Prior Period [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases, net of unearned discount	21,736,287	18,542,940
Term Loans Prior Period [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	201,254	162,666
Accruing Loans Past Due 90 Days or More	545,010	542,749
Nonaccrual	307,228	314,792
Loans and leases, net of unearned discount	7,098,305	6,933,668
Term Loans Prior Period [Member] | Residential Limited Documentation [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	16,546	16,666
Nonaccrual	123,512	122,888
Loans and leases, net of unearned discount	1,190,386	1,264,074
Term Loans Prior Period [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	935	698
Nonaccrual	5,445	5,750
Loans and leases, net of unearned discount	42,396	44,463
Term Loans Prior Period [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	8,651	7,123
Nonaccrual	11,688	7,996
Loans and leases, net of unearned discount	1,036,425	661,159
Term Loans Prior Period [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	6,501	3,129
Nonaccrual	10,320	5,463
Loans and leases, net of unearned discount	239,065	80,190
Term Loans Prior Period [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	5,814	5,712
Accruing Loans Past Due 90 Days or More	3,703	3,302
Nonaccrual	266	353
Loans and leases, net of unearned discount	36,708	23,688
Term Loans Prior Period [Member] | Current [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	6,044,813	5,913,461
Term Loans Prior Period [Member] | Current [Member] | Residential Limited Documentation [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,050,328	1,124,520
Term Loans Prior Period [Member] | Current [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	36,016	38,015
Term Loans Prior Period [Member] | Current [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,016,086	646,040
Term Loans Prior Period [Member] | Current [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	222,244	71,598
Term Loans Prior Period [Member] | Current [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	26,925	14,321
Term Loans 2020 [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases, net of unearned discount	11,573,793	12,376,366
Term Loans 2020 [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	10,756	12,535
Accruing Loans Past Due 90 Days or More	60,476	100,581
Nonaccrual	14,866	19,858
Loans and leases, net of unearned discount	1,743,887	1,805,064
Term Loans 2020 [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases, net of unearned discount	762	777
Term Loans 2020 [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	7,647	8,912
Nonaccrual	6,270	4,646
Loans and leases, net of unearned discount	1,952,572	2,101,900
Term Loans 2020 [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	5,104	6,615
Nonaccrual	5,904	4,390
Loans and leases, net of unearned discount	992,272	1,108,689
Term Loans 2020 [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	369	404
Nonaccrual	203	326
Loans and leases, net of unearned discount	86,034	97,675
Term Loans 2020 [Member] | Current [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,657,789	1,672,090
Term Loans 2020 [Member] | Current [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	762	777
Term Loans 2020 [Member] | Current [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,938,655	2,088,342
Term Loans 2020 [Member] | Current [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	981,264	1,097,684
Term Loans 2020 [Member] | Current [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	85,462	96,945
Term Loans 2019 [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases, net of unearned discount	11,481,256	12,286,933
Term Loans 2019 [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	5,952	9,886
Accruing Loans Past Due 90 Days or More	25,426	28,512
Nonaccrual	9,950	7,119
Loans and leases, net of unearned discount	1,034,082	1,121,413
Term Loans 2019 [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases, net of unearned discount	2,648	2,793
Term Loans 2019 [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	6,930	8,317
Nonaccrual	5,907	4,871
Loans and leases, net of unearned discount	1,188,261	1,281,117
Term Loans 2019 [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	6,824	8,936
Nonaccrual	8,199	7,847
Loans and leases, net of unearned discount	590,528	678,783
Term Loans 2019 [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	489	472
Nonaccrual	370	326
Loans and leases, net of unearned discount	62,338	74,384
Term Loans 2019 [Member] | Current [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	992,754	1,075,896
Term Loans 2019 [Member] | Current [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	2,648	2,793
Term Loans 2019 [Member] | Current [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,175,424	1,267,929
Term Loans 2019 [Member] | Current [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	575,505	662,000
Term Loans 2019 [Member] | Current [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	61,479	73,586
Term Loans 2018 [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases, net of unearned discount	7,237,064	7,895,140
Term Loans 2018 [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	6,882	6,132
Accruing Loans Past Due 90 Days or More	28,236	31,996
Nonaccrual	3,347	4,577
Loans and leases, net of unearned discount	442,361	508,745
Term Loans 2018 [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due		21
Loans and leases, net of unearned discount	1,480	1,751
Term Loans 2018 [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	4,076	5,074
Nonaccrual	5,017	4,918
Loans and leases, net of unearned discount	611,776	656,875
Term Loans 2018 [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	5,022	7,161
Nonaccrual	7,171	7,867
Loans and leases, net of unearned discount	301,538	356,683
Term Loans 2018 [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due	166	255
Nonaccrual	144	193
Loans and leases, net of unearned discount	19,385	24,872
Term Loans 2018 [Member] | Current [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	403,896	466,040
Term Loans 2018 [Member] | Current [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	1,480	1,730
Term Loans 2018 [Member] | Current [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	602,683	646,883
Term Loans 2018 [Member] | Current [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	289,345	341,655
Term Loans 2018 [Member] | Current [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans	$ 19,075	24,424
Term Loans 2017 [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases, net of unearned discount		5,558,871
Term Loans 2017 [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due		33,097
Accruing Loans Past Due 90 Days or More		205,318
Nonaccrual		5,890
Loans and leases, net of unearned discount		1,282,263
Term Loans 2017 [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases, net of unearned discount		1,944
Term Loans 2017 [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due		5,189
Nonaccrual		4,039
Loans and leases, net of unearned discount		455,096
Term Loans 2017 [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due		5,715
Nonaccrual		6,882
Loans and leases, net of unearned discount		224,371
Term Loans 2017 [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
30-89 Days Past Due		101
Nonaccrual		104
Loans and leases, net of unearned discount		17,129
Term Loans 2017 [Member] | Current [Member] | Residential [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans		1,037,958
Term Loans 2017 [Member] | Current [Member] | Home Equity Lines and Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans		1,944
Term Loans 2017 [Member] | Current [Member] | Recreational Finance [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans		445,868
Term Loans 2017 [Member] | Current [Member] | Automobile [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans		211,774
Term Loans 2017 [Member] | Current [Member] | Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total Loans		$ 16,924