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Goodwill and Core Deposit Intangibles - Schedule of Finite-Lived Intangible Assets (Details) - USD ($) $ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2022 | Mar. 31, 2023 | Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items] |  |  |
2024 |  | $ 14.6 |
Finite-lived Intangible Assets [Roll Forward] |  |  |
Finite-Lived Intangible Assets, Gross | $ 177.5 |  | $ 106.0
Finite-Lived Intangible Assets Acquired | 72.9 |  |
Finite-Lived Intangible Assets, Period Increase (Decrease) | (1.4) |  |
Finite-Lived Intangible Assets, Accumulated Amortization | (80.5) | (84.5) |
75900000 | 97.0 | 93.0 |
Core Deposits |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
2024 |  | 12.7 |
Finite-lived Intangible Assets [Roll Forward] |  |  |
Finite-Lived Intangible Assets, Gross | 154.7 |  | 106.0
Finite-Lived Intangible Assets Acquired | 50.1 |  |
Finite-Lived Intangible Assets, Period Increase (Decrease) | (1.4) |  |
Finite-Lived Intangible Assets, Accumulated Amortization | (78.8) | (82.3) |
75900000 | 75.9 | 72.4 |
OCRI |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
2024 |  | 1.9 |
Finite-lived Intangible Assets [Roll Forward] |  |  |
Finite-Lived Intangible Assets, Gross | 22.8 |  | $ 0.0
Finite-Lived Intangible Assets Acquired | 22.8 |  |
Finite-Lived Intangible Assets, Period Increase (Decrease) | 0.0 |  |
Finite-Lived Intangible Assets, Accumulated Amortization | (1.7) | (2.2) |
75900000 | $ 21.1 | $ 20.6 |

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