Loans and Allowance for Credit Losses for Loans - Past Due, Non-Accrual and Current Loans by Loan Portfolio Class (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Financing Receivable, Past Due [Line Items]
Loans	$ 49,391,420	$ 48,799,711
Non-Accrual Loans	354,359	359,498
Non-Accrual Loans Without Allowance for Loan Losses	157,655	136,928
Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	553,561	458,692
30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	122,957	57,138
60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	73,324	36,167
90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	2,921	5,889
Current Loans
Financing Receivable, Past Due [Line Items]
Loans	48,837,859	48,341,019
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans	10,870,036	9,931,400
Non-Accrual Loans	90,973	136,675
Non-Accrual Loans Without Allowance for Loan Losses	19,512	15,947
Commercial and industrial | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	102,519	141,378
Commercial and industrial | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	10,451	2,389
Commercial and industrial | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,095	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	10,767,517	9,790,022
Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans	28,825,920	29,644,958
Non-Accrual Loans	217,672	181,822
Non-Accrual Loans Without Allowance for Loan Losses	107,756	96,097
Commercial real estate | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	356,157	227,627
Commercial real estate | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	77,884	20,902
Commercial real estate | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	60,601	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	28,469,763	29,417,331
Commercial real estate | Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans	25,971,061	26,530,225
Non-Accrual Loans	193,604	157,231
Non-Accrual Loans Without Allowance for Loan Losses	107,756	91,095
Commercial real estate | Commercial real estate | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	297,089	203,036
Commercial real estate | Commercial real estate | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	42,884	20,902
Commercial real estate | Commercial real estate | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	60,601	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	25,673,972	26,327,189
Commercial real estate | Construction
Financing Receivable, Past Due [Line Items]
Loans	2,854,859	3,114,733
Non-Accrual Loans	24,068	24,591
Non-Accrual Loans Without Allowance for Loan Losses	0	5,002
Commercial real estate | Construction | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	59,068	24,591
Commercial real estate | Construction | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	35,000	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	2,795,791	3,090,142
Residential mortgage
Financing Receivable, Past Due [Line Items]
Loans	5,709,971	5,632,516
Non-Accrual Loans	41,099	36,786
Non-Accrual Loans Without Allowance for Loan Losses	29,064	23,543
Residential mortgage | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	72,532	67,387
Residential mortgage | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	21,744	21,295
Residential mortgage | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	7,627	5,773
Residential mortgage | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	2,062	3,533
Residential mortgage | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	5,637,439	5,565,129
Consumer loans
Financing Receivable, Past Due [Line Items]
Loans	3,985,493	3,590,837
Non-Accrual Loans	4,615	4,215
Non-Accrual Loans Without Allowance for Loan Losses	1,323	1,341
Consumer loans | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	22,353	22,300
Consumer loans | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	12,878	12,552
Consumer loans | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	4,001	4,484
Consumer loans | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	859	1,049
Consumer loans | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	3,963,140	3,568,537
Consumer loans | Home equity
Financing Receivable, Past Due [Line Items]
Loans	634,553	604,433
Non-Accrual Loans	4,391	3,961
Non-Accrual Loans Without Allowance for Loan Losses	1,323	1,341
Consumer loans | Home equity | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	8,783	5,793
Consumer loans | Home equity | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,893	1,651
Consumer loans | Home equity | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	2,499	181
Consumer loans | Home equity | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	0
Consumer loans | Home equity | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	625,770	598,640
Consumer loans | Automobile
Financing Receivable, Past Due [Line Items]
Loans	2,178,841	1,901,065
Non-Accrual Loans	209	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	11,471	10,566
Consumer loans | Automobile | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	9,710	8,583
Consumer loans | Automobile | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,113	1,346
Consumer loans | Automobile | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	439	407
Consumer loans | Automobile | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	2,167,370	1,890,499
Consumer loans | Other consumer
Financing Receivable, Past Due [Line Items]
Loans	1,172,099	1,085,339
Non-Accrual Loans	15	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	2,099	5,941
Consumer loans | Other consumer | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,275	2,318
Consumer loans | Other consumer | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	389	2,957
Consumer loans | Other consumer | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	420	642
Consumer loans | Other consumer | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	$ 1,170,000	$ 1,079,398