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Asset Retirement Obligations - Changes to Asset Retirement Obligation (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Asset retirement obligation at beginning of period $ 31.8 $ 27.8
Accretion expense 1.2 1.3
Liabilities Incurred 1.0
Revisions in estimated cash flows [1] (4.5) 3.5
Payments (0.1) (0.8)
Asset retirement obligation at end of period $ 29.4 $ 31.8
[1] For 2021 and 2020, primarily consists of an asset retirement adjustment of $4.2 million and $4.5 million, respectively, related to the San Lorenzo, California facility closure.