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Loans and Allowance for Credit Losses - Additional Information (Details) |  | 3 Months Ended | 9 Months Ended |
--- | --- | --- | --- | ---
Apr. 01, 2024 USD ($) | Sep. 30, 2024 USD ($) portfolio segment | Sep. 30, 2023 USD ($) | Sep. 30, 2024 USD ($) portfolio segment | Sep. 30, 2023 USD ($) | Dec. 31, 2023 USD ($)
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |  |
Loan participations |  | $ 3,400,000,000 |  | $ 3,400,000,000 |  |
Loan participations sold |  | 1,500,000,000 |  | 1,500,000,000 |  |
Loan participations retained |  | $ 1,900,000,000 |  | $ 1,900,000,000 |  |
Number of loan portfolios | portfolio |  | 4 |  | 4 |  |
Number of loan segments | segment |  | 7 |  | 7 |  |
Allowance for credit losses at acquisition | $ 26,725,000 |  |  |  |  |
Provision for credit losses |  | $ 28,497,000 | $ 19,068,000 | $ 83,602,000 | $ 47,292,000 |
Loan placed on nonaccrual when past due, number of days |  |  |  | 90 days |  |
Payment defaults |  | 3,900,000 | $ 0 | $ 25,300,000 | $ 0 |
Unfunded commitments on TDRs |  | 0 |  | 0 |  | $ 0
CapStar Financial Holdings, Inc. |  |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |  |
Allowance for credit losses at acquisition | $ 26,700,000 |  |  |  |  |
Provision for credit losses |  |  |  | 15,300,000 |  |
Accrued interest receivable on loans |  | $ 174,800,000 |  | $ 174,800,000 |  | $ 169,800,000
Commercial real estate |  |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |  |
Percentage of risk-based capital |  | 241.00% |  | 241.00% |  |
Regulatory guideline limit |  | 300.00% |  | 300.00% |  |

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- Definition Maximum number of days past due before loan is placed on nonaccrual status. + References No definition available. + Details
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- Definition Amount, before allowance for credit loss, of accrued interest on financing receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B + Details
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