Derivatives Derivatives - Schedule of Derivative Positions (WCS Crude Oil Basis Swaps) (Details) - WCS crude oil basis swaps - Fuel Product [Member] - Not Designated as Hedging Instrument [Member]	Mar. 31, 2020 bbl $ / bbl	Dec. 31, 2019 bbl $ / bbl
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	4,287,500	544,000
Average Swap ($/Bbl) | $ / bbl	(14.04)	(18.92)
First Quarter 2020
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount		544,000
Barrels per Day Purchased		5,978
Average Swap ($/Bbl) | $ / bbl		(18.92)
Second Quarter 2020
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	1,067,500
Barrels per Day Purchased	11,731
Average Swap ($/Bbl) | $ / bbl	(13.10)
Fourth Quarter 2020
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	1,610,000
Barrels per Day Purchased	17,500
Average Swap ($/Bbl) | $ / bbl	(15.02)
Third Quarter 2020
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	1,610,000
Barrels per Day Purchased	17,500
Average Swap ($/Bbl) | $ / bbl	(13.68)