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Benefit Plans - Allocation of Plan Assets (Details) - USD ($) $ in Millions | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |
Weighted average asset allocations | 100.00% | 100.00%
Fair value of plan assets | $ 249.2 | $ 258.1
Pension plan assets in the fair value hierarchy |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 49.5 | 43.7
Level 1 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 1.6 | 1.5
Level 2 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 47.9 | 42.2
Level 3 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 |
Pension plan assets measured at NAV |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 199.7 | 214.4
Cash | Pension plan assets in the fair value hierarchy |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 1.6 | 1.5
Cash | Level 1 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 1.6 | 1.5
Cash | Level 2 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Cash | Level 3 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 0.0 | $ 0.0
Equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Weighted average asset allocations | 12.00% | 34.00%
Equity securities | United States |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Target allocation | 5.00% |
Equity securities | Pension plan assets in the fair value hierarchy |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 21.2 | $ 20.6
Equity securities | Level 1 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Equity securities | Level 2 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 21.2 | 20.6
Equity securities | Level 3 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 0.0 | $ 0.0
Debt securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Weighted average asset allocations | 86.00% | 64.00%
Debt securities | United States |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Target allocation | 95.00% |
Other |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Weighted average asset allocations | 2.00% | 2.00%
Other | United States |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Target allocation | 0.00% |
Mutual funds | Pension plan assets in the fair value hierarchy |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 22.1 | $ 18.7
Mutual funds | Level 1 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Mutual funds | Level 2 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 22.1 | 18.7
Mutual funds | Level 3 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Other mutual funds | Pension plan assets in the fair value hierarchy |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 4.6 | 2.9
Other mutual funds | Level 1 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Other mutual funds | Level 2 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 4.6 | 2.9
Other mutual funds | Level 3 |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 0.0 | $ 0.0
Minimum | Equity securities | United States |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Weighted average asset allocations | 2.00% |
Minimum | Debt securities | United States |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Weighted average asset allocations | 92.00% |
Minimum | Other | United States |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Weighted average asset allocations | 0.00% |
Maximum | Equity securities | United States |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Weighted average asset allocations | 8.00% |
Maximum | Debt securities | United States |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Weighted average asset allocations | 98.00% |
Maximum | Other | United States |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Weighted average asset allocations | 3.00% |

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