Delek Logistics and the Alon Partnership Narrative (Details) $ in Millions		1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Dec. 31, 2017 shares	Mar. 31, 2018 USD ($)	Mar. 31, 2018 USD ($)	Jun. 30, 2018	Dec. 31, 2018 USD ($) shares	Feb. 07, 2018 USD ($) shares	Feb. 06, 2018 shares
Variable Interest Entity [Line Items]
Common stock, shares, issued (in shares) | shares	81,533,548				90,478,075
Acquisition related transaction costs					$ 3.0
Additional deferred tax expense recorded			$ 5.5
Alon USA Energy, Inc.
Variable Interest Entity [Line Items]
Limited partners' capital account, units outstanding (in shares) | shares							51,000,000.0
Ownership interest in general partner					100.00%
Delek Logistics | Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Limited partners' capital account, units outstanding (in shares) | shares					15,294,046
Ownership interest in general partner					94.60%
General partner units (in units) | shares					498,038
Alon Partnership | Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
General partner ownership interest in delek logistics				100.00%
Limited parters' capital account, units outstanding, held by public, percent	18.40%
Business combination, acquisition of less than 100 percent, noncontrolling interest, fair value					$ 120.6
Alon Partnership | Variable Interest Entity, Primary Beneficiary | Other Ownership Interest
Variable Interest Entity [Line Items]
Limited partners' capital account, units outstanding (in shares) | shares	11,500,000
Delek Logistics | Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Members or limited partners, ownership interest (percentage)					61.40%
Delek Logistics GP, LLC | Delek Logistics | Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
General partner ownership interest in delek logistics					2.00%
Big Spring Logistics Agreement
Variable Interest Entity [Line Items]
Payment to acquire business		$ 170.8
Alon Partnership | Limited Partner
Variable Interest Entity [Line Items]
Deferred tax assets, net of valuation allowance						$ 13.5
Alon Partnership | Alon USA Energy, Inc.
Variable Interest Entity [Line Items]
Members or limited partners, ownership interest (percentage)	81.60%
Alon Partnership | Variable Interest Entity, Primary Beneficiary | Alon USA Energy, Inc.
Variable Interest Entity [Line Items]
Members or limited partners, ownership interest (percentage)				81.60%
Big Spring Marketing Agreement
Variable Interest Entity [Line Items]
Payment to acquire business		144.2
Deferred tax assets, net of valuation allowance		$ 98.8	$ 98.8
New Delek Common Stock [Member] | Alon USA Energy, Inc.
Variable Interest Entity [Line Items]
Fixed exchange ratio of shares						0.49
Common stock, shares, issued (in shares) | shares						5,600,000