Crude Oil Supply and Inventory Purchase Agreement (Details) bbl in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) bbl / pure bbl	Dec. 31, 2017 USD ($) bbl	Dec. 31, 2016 USD ($)
El Dorado Refinery
Receivable related to monthly settlement	$ 7.8	$ 0.3
Alon Refinery
Purchase settlement payable	$ 1.0	$ 4.4
J. Aron & Company | El Dorado Refinery
Inventory consigned to J Aron (barrels) | bbl	2.8	3.0
Liability for inventory consigned to J Aron	$ 152.6	$ 181.9
Issued letters of credit	120.0	95.0
J. Aron & Company | El Dorado Refinery | Interest Expense
Inventory financing expense	$ 10.7	$ 9.7	$ 9.7
J. Aron & Company | Alon Refinery
Inventory consigned to J Aron (barrels) | bbl	1.8	3.5
Liability for inventory consigned to J Aron	$ 113.1	$ 253.7
Issued letters of credit	24.0	10.0
J. Aron & Company | Alon Refinery | Interest Expense
Inventory financing expense	$ 13.8	$ 7.1
J. Aron & Company | El Dorado Refinery
Maximum barrels per day supplied under supply and offtake agreement (bpd)	100,000
J. Aron & Company | Alon Refinery
Oil and gas delivery commitments and contracts, right to terminate, period of required prior notice	6 months
Other current liabilities
Supply and offtake payable	$ 46.9
Other current liabilities | J. Aron & Company | Alon Refinery
Inventory consigned to J Aron (barrels) | bbl	0.9
Baseline Step-Out Liability | J. Aron & Company | Alon Refinery
Inventory consigned to J Aron (barrels) | bbl	0.8
Gain (loss) on modification of instruments from commodities-based risk to interest rate risk	$ 4.0
Fixed notional amount outstanding for barrels of baseline consigned inventory	52.0
Unamortized discount of notional amount under Supply and Offtake Agreement	2.4
Fair value of notional amount under Supply and Offtake Agreement	$ 49.6