Segment Data - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($) store facility	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) bbl / pure store facility	Jun. 30, 2017 USD ($)	Jul. 01, 2017 store
Segment Reporting Information [Line Items]
Refinery throughput capacity (in bpd)			155,000
Number of stores | store	300		300		300
Tyler Refinery
Segment Reporting Information [Line Items]
Refinery throughput capacity (in bpd)			75,000
El Dorado Refinery
Segment Reporting Information [Line Items]
Refinery throughput capacity (in bpd)			80,000
Krotz Springs, Louisiana
Segment Reporting Information [Line Items]
Refinery throughput capacity (in bpd)			74,000
Big Spring, Texas
Segment Reporting Information [Line Items]
Refinery throughput capacity (in bpd)			73,000
Refining
Segment Reporting Information [Line Items]
Number of biodiesel facilities | facility	2		2
Refining | Operating Segments
Segment Reporting Information [Line Items]
Intercompany fees and sales		$ 8.2		$ 17.2
Refining | RIN Sales
Segment Reporting Information [Line Items]
Intercompany fees and sales	$ 0.7	1.2	$ 2.0	2.3
Refining | Products and Services to Retail Segment
Segment Reporting Information [Line Items]
Intercompany fees and sales	118.9		218.4
Refining | Asphalt
Segment Reporting Information [Line Items]
Intercompany fees and sales	7.7		11.1
Logistics
Segment Reporting Information [Line Items]
Intercompany fees and sales	99.5		181.8
Logistics | Crude Transportation and Storage Fees
Segment Reporting Information [Line Items]
Intercompany fees and sales	43.6	33.1	97.9	64.3
Tyler Refinery | Logistics | Refining Marketing Services
Segment Reporting Information [Line Items]
Intercompany fees and sales	5.5	$ 5.3	10.5	$ 9.6
Big Spring refinery | Logistics | Refining Marketing Services
Segment Reporting Information [Line Items]
Intercompany fees and sales	$ 3.2		$ 4.3