Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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- Details

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Namespace Prefix:
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Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=dk_AlonEnergyTermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=dk_AlongAsphaltTermLoanMember
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Data Type:	na
Balance Type:
Period Type:

Long-Term Obligations and Notes Payable - Alon Term Loan Credit Facilities (Details) - Term loan - USD ($)		6 Months Ended	12 Months Ended
	Mar. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Mar. 27, 2014
Debt Instrument [Line Items]
Face amount of debt	$ 700,000,000
Principal installments	$ 1,750,000
London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread (as percent)	2.50%
Alon Energy Term Loan
Debt Instrument [Line Items]
Face amount of debt				$ 25,000,000.0
New Alon Energy Term Loan
Debt Instrument [Line Items]
Face amount of debt				$ 38,000,000.0
Principal installments			$ 1,400,000
New Alon Energy Term Loan \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread (as percent)			3.75%
Along Asphalt Term Loan
Debt Instrument [Line Items]
Face amount of debt		$ 35,000,000.0
Principal installments		$ 3,900,000
Along Asphalt Term Loan \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread (as percent)		3.75%