Crude Oil Supply and Inventory Purchase Agreement (Details) bbl in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($) bbl	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) bbl / pure bbl	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) bbl
El Dorado Refinery
Oil and Gas Delivery Commitments and Contracts [Line Items]
(Payable) receivable recorded related to monthly settlement	$ (6.9)		$ (6.9)		$ 0.3
El Dorado Refinery | J. Aron
Oil and Gas Delivery Commitments and Contracts [Line Items]
Barrels of Inventory Consigned to J Aron | bbl	2.9		2.9		3.0
Liabilities recorded associated with consigned inventory	$ 202.6		$ 202.6		$ 181.9
El Dorado Refinery | J. Aron | Interest expense
Oil and Gas Delivery Commitments and Contracts [Line Items]
Inventory financing expense	2.9	$ 2.5	$ 5.6	$ 4.9
El Dorado Refinery | J. Aron
Oil and Gas Delivery Commitments and Contracts [Line Items]
Maximum barrels per day supplied under Supply and Offtake Agreement (bpd)			100,000
Alon Refinery
Oil and Gas Delivery Commitments and Contracts [Line Items]
Period of prior notice required to terminate Supply and Offtake Agreement			6 months
Purchase Settlement Payable	$ (17.9)		$ (17.9)		$ (4.4)
Alon Refinery | J. Aron
Oil and Gas Delivery Commitments and Contracts [Line Items]
Barrels of Inventory Consigned to J Aron | bbl	3.2		3.2		3.5
Liabilities recorded associated with consigned inventory	$ 268.6		$ 268.6		$ 253.7
Alon Refinery | J. Aron | Interest expense
Oil and Gas Delivery Commitments and Contracts [Line Items]
Inventory financing expense	$ 3.6		$ 6.9
Alon Refinery | J. Aron
Oil and Gas Delivery Commitments and Contracts [Line Items]
Period of prior notice required to terminate Supply and Offtake Agreement			6 months