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Goodwill and Other Intangible Assets - Additional Information (Details) - USD ($) |  | 3 Months Ended | 9 Months Ended |  |
--- | --- | --- | --- | --- | ---
Aug. 31, 2025 | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | May 01, 2025 | Apr. 01, 2024
Goodwill [Line Items] |  |  |  |  |  |  |
Goodwill impairment | $ 0 |  |  |  |  |  |
Impairment charges |  |  |  | $ 0 | $ 0 |  |
Amortization of other intangible assets |  | $ 26,184,000 | $ 7,411,000 | $ 52,644,000 | 20,291,000 |  |
Minimum | Core Deposits and Other Intangible Assets |  |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |  |
Estimated useful lives |  | 5 years |  | 5 years |  |  |
Maximum | Core Deposits and Other Intangible Assets |  |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |  |
Estimated useful lives |  | 15 years |  | 15 years |  |  |
Bremer |  |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |  |
Goodwill |  |  |  | $ 243,400,000 |  |  |
Bremer | Core deposit |  |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |  |
Estimated useful lives |  |  |  |  |  | 10 years |
Estimated fair value of intangible assets acquired |  |  |  | 397,100,000 |  |  |
Bremer | Customer relationship |  |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |  |
Estimated useful lives |  |  |  |  |  | 12 years |
Estimated fair value of intangible assets acquired |  |  |  | $ 43,000,000 |  |  |
CapStar Financial Holdings, Inc. |  |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |  |
Goodwill |  |  |  |  | $ 178,300,000 |  |
CapStar Financial Holdings, Inc. | Core deposit |  |  |  |  |  |  |
Goodwill [Line Items] |  |  |  |  |  |  |
Estimated useful lives |  |  |  |  |  |  | 10 years

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