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Employee Benefit Plans (Details) - USD ($) $ in Millions | 2 Months Ended | 4 Months Ended | 12 Months Ended
--- | --- | --- | ---
Dec. 31, 2021 | Oct. 19, 2021 | Dec. 31, 2023 | Dec. 31, 2022 | Jun. 30, 2021
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Unrealized gain on pension and postretirement benefit plans, net of tax |  |  | $ (1.2) | $ 1.5 |
Estimated future benefit payments |  |  | 4.9 |  |
Benefits expense | $ 0.6 | $ 1.0 | 3.0 | 2.5 | $ 3.7
Defined Benefit Pension Plans |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Benefit obligation |  |  | 9.0 | 8.2 |
Business expense | $ 0.3 | $ 0.3 | 1.1 | 1.3 | $ 1.2
Other Postretirement Benefit Plans |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Benefit obligation |  |  | $ 0.5 | $ 0.5 |

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