XML 73 R7.htm IDEA: XBRL DOCUMENT
v3.20.1

Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) | 3 Months Ended
--- | ---
Mar. 31, 2020 | Mar. 31, 2019
General Partnership [Member] |  |
General partner's ownership interest (as percent) | 2.00% | 2.00%

X
- Definition Percentage investment held by the managing member or general partner of the limited liability company (LLC) or limited partnership (LP). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 272 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055 + Details
Name: | us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_OwnershipAxis=dk_GeneralPartnershipMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |