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Property, Plant and Equipment - Narrative (Details) - $ / Boe
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Property, Plant and Equipment [Line Items]      
Average depreciation and depletion rate (usd per Boe) 12.28 10.32 7.92
Expected completion of evaluation activities on majority of unproved properties 10 years    
Minimum      
Property, Plant and Equipment [Line Items]      
Expect completion of evaluation activities on majority of unproved properties, without existing production 3 years    
Maximum      
Property, Plant and Equipment [Line Items]      
Expect completion of evaluation activities on majority of unproved properties, without existing production 5 years