Commitments and Contingencies - Environmental Health and Safety (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Other current liabilities
Loss Contingencies [Line Items]
Environmental liabilities, current		$ 3.8
El Dorado refinery prior owner case
Loss Contingencies [Line Items]
Estimated time frame to resolve contingency	P30Y
Accrual for Environmental Loss Contingencies, Including Undiscounted Amounts	$ 143.2
El Dorado refinery prior owner case | Other current liabilities
Loss Contingencies [Line Items]
Environmental liabilities, current	$ 3.7
Alon | Big Spring refinery
Loss Contingencies [Line Items]
Negotiation period	10 years
Required payment estimated upon finalization of the Consent Decree	$ 0.5
Estimated time frame to resolve contingency	P10Y
Magnolia Station Spill [Member] | Magnolia Station Spill [Member] | Other current liabilities
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies	$ 2.2