Overview (Details) bbl / d in Thousands	12 Months Ended
	Dec. 31, 2020 bbl / d gasoline_convenience_store_facility retail_site segment refinery	Dec. 31, 2020 bbl / d gasoline_convenience_store_facility retail_site refinery	Dec. 31, 2020 bbl / d retail_site gasoline_convenience_store_facility refinery	Oct. 18, 2018	Feb. 28, 2018	Mar. 01, 2016
Operating segments | segment	3
Number of owned and operated refineries | refinery	4	4	4
Oil and gas refinery | bbl / d	150	150	150
Number of retail outlets	123	123	123
Convenience store facilities	34	34	34
Number of fueling stations, rebranded		42	4
Kauai Automated Fuels
Number of branded retail sites | retail_site	8	8	8
Cenex Zip Trip
Number of retail outlets	33	33	33
Laramie Energy Company
Ownership of Laramie Energy, LLC	46.00%	46.00%	46.00%	46.00%	39.10%	42.30%