Variable Interest Entity Arrangements (Details) - Superior Pipeline Company, L.L.C. [Member]	3 Months Ended
Mar. 31, 2019 USD ($)
Variable Interest Entity [Line Items]
Date Involvement Began	Apr. 03, 2018
Methodology for Determining Whether Entity is Primary Beneficiary	The two variable interests applicable to Unit include the 50% equity investment in Superior and the MSA. The MSA houses the power to direct the activities that most significantly impact Superior's operating performance. The MSA is a separate variable interest. Unit through the MSA has the power to direct Superior’s most significant activities; reciprocally the equity investors lack the power to direct the activities that most significantly impact the entity’s economic performance. Because of this, Unit is considered the primary beneficiary.
Lack of Recourse	Superior's creditors have no recourse to our general credit.
SP Investor Holdings, LLC [Member]
Variable Interest Entity [Line Items]
Ownership Percentage	50.00%
SPC Midstream Operating, L.L.C. [Member]
Variable Interest Entity [Line Items]
Monthly service fee	$ 255,970

The degree to which creditors (or beneficial interest holders) of the Variable Interest Entity (VIE) have recourse against the general credit of the primary beneficiary.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph c
-URI http://asc.fasb.org/extlink&oid=108788376&loc=d3e5710-111685

+ Details

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

- 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

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

- Definition

Description of significant judgments and assumptions made by a reporting entity in determining whether it must: (1) consolidate a Variable Interest Entity (VIE) or (2) disclose information about its involvement in a VIE, and may include discussion of the significant factors considered and judgments made in determining that the power to direct the activities of a VIE that most significantly impact the VIE's economic performance is shared among multiple parties such that no one party is the primary beneficiary (as defined) or information about the types of involvements the reporting entity considers significant, supplemented with information about how the significant involvements were considered in determining whether the reporting entity is the primary beneficiary.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=108788376&loc=SL6759159-111685

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 2AA
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=108788376&loc=SL6759068-111685

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=108788376&loc=d3e5728-111685

+ Details

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

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

+ Details

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

- Definition

Date the relationship between reporting entity and the Variable Interest Entity (VIE) began, in CCYY-MM-DD format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph b
-URI http://asc.fasb.org/extlink&oid=108788376&loc=d3e5747-111685

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=108788376&loc=SL6759159-111685

+ Details

Name:	us-gaap_VariableInterestEntityQualitativeOrQuantitativeInformationDateInvolvementBegan1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Monthly service fee

+ References

No definition available.

+ Details

Name:	wfx_Monthlyservicefee
Namespace Prefix:	wfx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=wfx_SuperiorPipelineCompanyL.L.C.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=wfx_SPInvestorHoldingsLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=wfx_SPCMidstreamOperatingL.L.C.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: