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Property, Plant and Equipment - Schedule of Asset Retirement Obligations (Parenthetical) (Details)
$ in Millions
12 Months Ended
Dec. 31, 2020
USD ($)
ILX and Castex  
Property, Plant and Equipment [Line Items]  
Fair value of asset retirement obligations assumed $ 35.3
Castex 2005 Acquisition  
Property, Plant and Equipment [Line Items]  
Fair value of asset retirement obligations assumed 3.3
LLOG Acquisition  
Property, Plant and Equipment [Line Items]  
Fair value of asset retirement obligations assumed $ 4.2