Cash Received From General Partner For Additional Shares Issued

No definition available.

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Namespace Prefix:	shlx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Gross proceeds from issuance of private placement, prior to any placement fees.

+ References

No definition available.

+ Details

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Namespace Prefix:	shlx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Partners' Capital, Sale of Units, Maximum Gross Proceeds

+ References

No definition available.

+ Details

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Namespace Prefix:	shlx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Placement agent fees in connection with the private placement.

+ References

No definition available.

+ Details

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Namespace Prefix:	shlx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

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Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- 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://www.xbrl.org/2003/role/presentationRef
-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

- Definition

Monetary value of the issuance of new units of limited partnership interest in a private placement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB TOPIC 4.F)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

+ Details

Name:	us-gaap_PartnersCapitalAccountPrivatePlacementOfUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The number of units sold in a private placement of each class of partners' capital account. Units represent shares of ownership of the general, limited, and preferred partners.

+ References

+ Details

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

- Definition

Per share or per unit amount of equity securities issued.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

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Namespace Prefix:
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Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=shlx_FiveYearRevolverMember
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- Details

Name:	us-gaap_DebtInstrumentAxis=shlx_ThreeHundredSixtyFourDayRevolverMember
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- Details

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=us-gaap_GeneralPartnerMember
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- Details

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- Details

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=shlx_CommonUnitsMember
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Equity - At-the-Market Program (Details) - USD ($)			3 Months Ended		12 Months Ended
Equity - At-the-Market Program (Details) - USD ($)	Mar. 29, 2016	Mar. 02, 2016	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Class of Stock [Line Items]
Issuance of common units, maximum (in units)		$ 300,000,000
Consideration for units issued in connection with private placement			$ 0	$ 8,700,000
Aggregate percentage of general partner interest			2.00%
Shell Treasury Center West Inc \| Five Year Revolver
Class of Stock [Line Items]
Debt instrument term			5 years
Shell Treasury Center West Inc \| 364 Day Revolver
Class of Stock [Line Items]
Debt instrument term			364 days		364 days
General Partner
Class of Stock [Line Items]
Units issued in connection with private placement (in units)				15,307
Consideration for units issued in connection with private placement	$ 8,200,000			$ 500,000
Aggregate percentage of general partner interest	2.00%		2.00%	2.00%
General Public \| Common Units
Class of Stock [Line Items]
Units issued in connection with private placement (in units)				750,000
Net proceeds from public offerings				$ 25,400,000
Gross proceed issuance of private placement offering				$ 25,500,000
Common units per share (in units per share)	$ 31.75			$ 34.00
Placement fees	$ 200,000			$ 100,000