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Property, Plant and Equipment - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Property, Plant and Equipment [Line Items]      
Amounts of assets held under finance leases $ 210.8 $ 198.7  
Depreciation charges 24.7 23.6 $ 22.6
Tangible Asset Impairment Charges 2.0 0.0 $ 0.0
Octane Additives [Member]      
Property, Plant and Equipment [Line Items]      
Tangible Asset Impairment Charges 2.0    
Assets Held under Capital Leases [Member]      
Property, Plant and Equipment [Line Items]      
Amounts of assets held under finance leases $ 1.0 $ 1.8