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Loans and Allowance for Loan Losses - Narrative (Details) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) contract | Dec. 31, 2021 USD ($) contract | Dec. 31, 2020 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans and leases receivable, impaired, interest lost on nonaccrual loans | $ 23,000,000 | $ 9,000,000 |  |
Cash-basis interest income recognized | 19,800,000 | 3,000,000 |  |
Loans | $ 43,404,490,000 | 43,716,353,000 |  |
Land held for future development, period | 1 year |  |  |
Financing receivable, allowance for credit loss | $ 479,385,000 | 443,424,000 | $ 427,597,000 | $ 605,736,000
Reserve for unfunded commitments | 57,200,000 | 57,500,000 |  |
All financing receivable, allowance for credit loss | 536,600,000 | 500,900,000 |  |
ACL increase | $ 35,700,000 |  |  |
ACL to loans ratio | 1.24% |  |  |
Increase in ACL to loans ratio | 0.0009 |  |  |
Allowance for credit loss, reasonable and supportable forecast period | 2 years |  |  |
Allowance for credit loss, straight-line basis historical period | 1 year |  |  |
Modifications, post-modification recorded investment |  | 131,186,000 | 48,932,000 |
Commitments to lend additional funds to TDRs |  | 0 |  |
Consumer |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Charge-off of previously established reserves for credit losses associated with the transfer to held for sale | $ 31,300,000 |  |  |
Reclassification to held-for-sale | 1,590,000,000 |  |  |
Financing receivable, allowance for credit loss | $ 126,657,000 | $ 138,299,000 | $ 141,473,000 | $ 245,439,000
Troubled Debt Restructuring That Subsequently Defaulted |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Subsequent default, number of contracts | contract |  | 5 | 8 |
Modifications, post-modification recorded investment |  | $ 1,000,000 | $ 978,000 |
Baseline |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Estimated unemployment rate | 4.50% |  |  |
Substandard |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Retail loan substandard period (in days) | 90 days |  |  |
Loss |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Retail loan charge off (in days) | 120 days |  |  |
Commercial & Industrial |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans | $ 22,598,493,000 | 22,066,656,000 |  |
Modifications, post-modification recorded investment |  | 105,610,000 | $ 27,618,000 |
Asset Pledged as Collateral |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans | $ 24,310,000,000 | $ 16,090,000,000.00 |  |

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