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_
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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

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Namespace Prefix:	us-gaap_
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

+ Details

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

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

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- Details

Name:	us-gaap_CreditFacilityAxis=dk_TermLoanFacilityMember
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- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Balance Type:
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- Details

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Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_VariableRateAxis=us-gaap_InterestRateFloorMember
Namespace Prefix:
Data Type:	na
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- Details

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Long-Term Obligations and Notes Payable Lion Term Loan Narrative (Details) - USD ($)	May 14, 2015	Dec. 31, 2017	May 13, 2015
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,483,100,000
Lion Term Loan
Debt Instrument [Line Items]
Long-term debt, gross		206,300,000
Term loan facility \| Secured Debt \| Lion Term Loan
Debt Instrument [Line Items]
Periodic payment, principal	$ 6,900,000
Long-term debt, gross		$ 206,300,000
Weighted average interest rate (percentage)		6.20%
Term loan facility \| Secured Debt \| Lion Term Loan \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Debt instrument, description of variable rate basis	LIBOR
Term loan facility \| Secured Debt \| Lion Term Loan \| Base Rate
Debt Instrument [Line Items]
Debt instrument, description of variable rate basis	base rate
Term loan facility \| Secured Debt \| Lion Term Loan \| Interest Rate Floor
Debt Instrument [Line Items]
Debt instrument, description of variable rate basis	interest rate floor
Debt instrument, basis spread on variable rate	5.50%
Fifth Third Bank \| Term loan facility \| Secured Debt \| Lion Term Loan
Debt Instrument [Line Items]
Debt instrument, face amount	$ 275,000,000.0		$ 99,000,000.0