Derivatives Derivatives - Schedule of Derivative Positions (Diesel Crack Spread Swaps) (Details) - Diesel crack spread swaps - Fuel Product [Member] - Not Designated as Hedging Instrument [Member]	Jun. 30, 2020 bbl $ / bbl	Dec. 31, 2019 bbl $ / bbl
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	736,000	1,615,500
Average Swap ($/Bbl) | $ / bbl	22.07	22.00
First Quarter 2020
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount		500,500
Barrels per Day Purchased		5,500
Average Swap ($/Bbl) | $ / bbl		22.15
Second Quarter 2020
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount		379,000
Barrels per Day Purchased		4,165
Average Swap ($/Bbl) | $ / bbl		21.68
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	22.23	22.23
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	21.91	21.91