Loans and Allowance for Credit Losses for Loans - Past Due, Non-Accrual and Current Loans by Loan Portfolio Class (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Financing Receivable, Past Due [Line Items]
Loans	$ 49,355,319	$ 50,210,295
Non-Accrual Loans	296,319	291,871
Non-Accrual Loans Without Allowance for Loan Losses	115,959	115,126
Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	471,015	383,497
30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	115,128	59,214
60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	54,788	19,267
90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	4,780	13,145
Current Loans
Financing Receivable, Past Due [Line Items]
Loans	48,884,304	49,826,798
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans	9,799,287	9,230,543
Non-Accrual Loans	120,575	99,912
Non-Accrual Loans Without Allowance for Loan Losses	25,626	6,594
Commercial and industrial | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	128,136	119,893
Commercial and industrial | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	4,537	9,307
Commercial and industrial | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,238	5,095
Commercial and industrial | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,786	5,579
Commercial and industrial | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	9,671,151	9,110,650
Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans	30,402,196	31,970,047
Non-Accrual Loans	138,409	160,590
Non-Accrual Loans Without Allowance for Loan Losses	69,833	93,289
Commercial real estate | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	258,705	168,845
Commercial real estate | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	76,370	3,008
Commercial real estate | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	43,926	1,257
Commercial real estate | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	3,990
Commercial real estate | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	30,143,491	31,801,202
Commercial real estate | Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans	26,914,732	28,243,239
Non-Accrual Loans	113,752	99,739
Non-Accrual Loans Without Allowance for Loan Losses	67,610	81,282
Commercial real estate | Commercial real estate | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	234,048	104,004
Commercial real estate | Commercial real estate | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	76,370	3,008
Commercial real estate | Commercial real estate | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	43,926	1,257
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	26,680,684	28,139,235
Commercial real estate | Construction
Financing Receivable, Past Due [Line Items]
Loans	3,487,464	3,726,808
Non-Accrual Loans	24,657	60,851
Non-Accrual Loans Without Allowance for Loan Losses	2,223	12,007
Commercial real estate | Construction | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	24,657	64,841
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	3,990
Commercial real estate | Construction | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	3,462,807	3,661,967
Residential mortgage
Financing Receivable, Past Due [Line Items]
Loans	5,684,079	5,569,010
Non-Accrual Loans	33,075	26,986
Non-Accrual Loans Without Allowance for Loan Losses	19,819	14,654
Residential mortgage | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	61,447	64,019
Residential mortgage | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	19,549	26,345
Residential mortgage | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	6,892	8,200
Residential mortgage | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,931	2,488
Residential mortgage | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	5,622,632	5,504,991
Consumer loans
Financing Receivable, Past Due [Line Items]
Loans	3,469,757	3,440,695
Non-Accrual Loans	4,260	4,383
Non-Accrual Loans Without Allowance for Loan Losses	681	589
Consumer loans | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	22,727	30,740
Consumer loans | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	14,672	20,554
Consumer loans | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	2,732	4,715
Consumer loans | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,063	1,088
Consumer loans | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	3,447,030	3,409,955
Consumer loans | Home equity
Financing Receivable, Past Due [Line Items]
Loans	581,181	559,152
Non-Accrual Loans	3,997	3,539
Non-Accrual Loans Without Allowance for Loan Losses	681	0
Consumer loans | Home equity | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	6,951	5,839
Consumer loans | Home equity | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,967	1,687
Consumer loans | Home equity | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	987	613
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	574,230	553,313
Consumer loans | Automobile
Financing Receivable, Past Due [Line Items]
Loans	1,823,738	1,620,389
Non-Accrual Loans	234	212
Non-Accrual Loans Without Allowance for Loan Losses	0	0
Consumer loans | Automobile | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	10,859	14,493
Consumer loans | Automobile | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	8,666	11,850
Consumer loans | Automobile | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,128	1,855
Consumer loans | Automobile | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	831	576
Consumer loans | Automobile | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	1,812,879	1,605,896
Consumer loans | Other consumer
Financing Receivable, Past Due [Line Items]
Loans	1,064,838	1,261,154
Non-Accrual Loans	29	632
Non-Accrual Loans Without Allowance for Loan Losses	0	589
Consumer loans | Other consumer | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	4,917	10,408
Consumer loans | Other consumer | 30-59  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	4,039	7,017
Consumer loans | Other consumer | 60-89  Days  Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	617	2,247
Consumer loans | Other consumer | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	232	512
Consumer loans | Other consumer | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	$ 1,059,921	$ 1,250,746