Derivatives Derivatives - Schedule of Derivative Positions (Gasoline Crack Spread Swaps) (Details) - Gasoline Crack Spread Swaps - Not Designated as Hedging Instrument [Member] - Fuel Product [Member]	Jun. 30, 2020 bbl $ / bbl	Dec. 31, 2019 bbl $ / bbl
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	736,000	1,706,500
Average Swap ($/Bbl) | $ / bbl	12.50	13.38
First Quarter 2020
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount		591,500
Barrels per Day Purchased		6,500
Average Swap ($/Bbl) | $ / bbl		12.54
Second Quarter 2020
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount		379,000
Barrels per Day Purchased		4,165
Average Swap ($/Bbl) | $ / bbl		16.41
Third Quarter 2020
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	368,000	368,000
Barrels per Day Purchased	4,000	4,000
Average Swap ($/Bbl) | $ / bbl	15.24	15.24
Fourth Quarter 2020
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	368,000	368,000
Barrels per Day Purchased	4,000	4,000
Average Swap ($/Bbl) | $ / bbl	9.77	9.77