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Goodwill and Intangible Assets - Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Goodwill [Line Items]      
Amortization expense $ 2.7 $ 2.7 $ 2.7
Average useful life 13 years 6 months    
Refining      
Goodwill [Line Items]      
Impairment expense $ 38.1    
Retail      
Goodwill [Line Items]      
Impairment expense $ 29.8