Loans and Allowance for Credit Losses for Loans - Past Due, Non-Accrual and Current Loans by Loan Portfolio Class (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Financing Receivable, Past Due [Line Items]
Loans	$ 48,657,128	$ 48,799,711
Non-Accrual Loans	346,451	359,498
Non-Accrual Loans Without Allowance for Loan Losses	179,083	136,928
Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	398,148	458,692
30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	33,413	57,138
60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	10,528	36,167
90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	7,756	5,889
Current Loans
Financing Receivable, Past Due [Line Items]
Loans	48,258,980	48,341,019
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans	10,150,205	9,931,400
Non-Accrual Loans	110,146	136,675
Non-Accrual Loans Without Allowance for Loan Losses	20,402	15,947
Commercial and industrial | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	114,175	141,378
Commercial and industrial | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	3,609	2,389
Commercial and industrial | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	420	1,007
Commercial and industrial | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	1,307
Commercial and industrial | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	10,036,030	9,790,022
Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans	29,114,556	29,644,958
Non-Accrual Loans	196,286	181,822
Non-Accrual Loans Without Allowance for Loan Losses	132,706	96,097
Commercial real estate | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	196,456	227,627
Commercial real estate | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	170	20,902
Commercial real estate | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	24,903
Commercial real estate | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	0
Commercial real estate | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	28,918,100	29,417,331
Commercial real estate | Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans	26,087,621	26,530,225
Non-Accrual Loans	172,011	157,231
Non-Accrual Loans Without Allowance for Loan Losses	128,229	91,095
Commercial real estate | Commercial real estate | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	172,181	203,036
Commercial real estate | Commercial real estate | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	170	20,902
Commercial real estate | Commercial real estate | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	24,903
Commercial real estate | Commercial real estate | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	0
Commercial real estate | Commercial real estate | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	25,915,440	26,327,189
Commercial real estate | Construction
Financing Receivable, Past Due [Line Items]
Loans	3,026,935	3,114,733
Non-Accrual Loans	24,275	24,591
Non-Accrual Loans Without Allowance for Loan Losses	4,477	5,002
Commercial real estate | Construction | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	24,275	24,591
Commercial real estate | Construction | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	0
Commercial real estate | Construction | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	0
Commercial real estate | Construction | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	0
Commercial real estate | Construction | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	3,002,660	3,090,142
Residential mortgage
Financing Receivable, Past Due [Line Items]
Loans	5,636,407	5,632,516
Non-Accrual Loans	35,393	36,786
Non-Accrual Loans Without Allowance for Loan Losses	24,643	23,543
Residential mortgage | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	66,732	67,387
Residential mortgage | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	16,747	21,295
Residential mortgage | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	7,700	5,773
Residential mortgage | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	6,892	3,533
Residential mortgage | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	5,569,675	5,565,129
Consumer loans
Financing Receivable, Past Due [Line Items]
Loans	3,755,960	3,590,837
Non-Accrual Loans	4,626	4,215
Non-Accrual Loans Without Allowance for Loan Losses	1,332	1,341
Consumer loans | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	20,785	22,300
Consumer loans | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	12,887	12,552
Consumer loans | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	2,408	4,484
Consumer loans | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	864	1,049
Consumer loans | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	3,735,175	3,568,537
Consumer loans | Home equity
Financing Receivable, Past Due [Line Items]
Loans	602,161	604,433
Non-Accrual Loans	4,363	3,961
Non-Accrual Loans Without Allowance for Loan Losses	1,332	1,341
Consumer loans | Home equity | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	6,433	5,793
Consumer loans | Home equity | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,661	1,651
Consumer loans | Home equity | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	379	181
Consumer loans | Home equity | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	30	0
Consumer loans | Home equity | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	595,728	598,640
Consumer loans | Automobile
Financing Receivable, Past Due [Line Items]
Loans	2,041,227	1,901,065
Non-Accrual Loans	242	230
Non-Accrual Loans Without Allowance for Loan Losses	0	0
Consumer loans | Automobile | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	10,652	10,566
Consumer loans | Automobile | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	8,508	8,583
Consumer loans | Automobile | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,454	1,346
Consumer loans | Automobile | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	448	407
Consumer loans | Automobile | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	2,030,575	1,890,499
Consumer loans | Other consumer
Financing Receivable, Past Due [Line Items]
Loans	1,112,572	1,085,339
Non-Accrual Loans	21	24
Non-Accrual Loans Without Allowance for Loan Losses	0	0
Consumer loans | Other consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	3,700	5,941
Consumer loans | Other consumer | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	2,718	2,318
Consumer loans | Other consumer | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	575	2,957
Consumer loans | Other consumer | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	386	642
Consumer loans | Other consumer | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	$ 1,108,872	$ 1,079,398