Cost method investment ownership percentage.

No definition available.

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Namespace Prefix:	shlx_
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Period Type:	instant

- Definition

Description of business and basis of presentation.

+ References

No definition available.

+ Details

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Namespace Prefix:	shlx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of Pipeline Systems

+ References

No definition available.

+ Details

Name:	shlx_NumberofPipelineSystems
Namespace Prefix:	shlx_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of Refined Products Systems

+ References

No definition available.

+ Details

Name:	shlx_NumberofRefinedProductsSystems
Namespace Prefix:	shlx_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

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

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

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

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
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- Details

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Description of the Business and Basis of Presentation - Additional Information (Details)	3 Months Ended
	Mar. 31, 2016 segment system	Dec. 31, 2015	Mar. 31, 2015
Description Of Business And Basis Of Presentation [Line Items]
Number of pipeline systems	4
Number of refined products systems	2
Number of reportable segments \| segment	1
Zydeco
Description Of Business And Basis Of Presentation [Line Items]
Minority interest ownership percentage by parent	62.50%
Minority interest ownership percentage by noncontrolling owners	37.50%	37.50%	57.00%
Colonial
Description Of Business And Basis Of Presentation [Line Items]
Cost method investment percentage	3.00%
Mars
Description Of Business And Basis Of Presentation [Line Items]
Equity method investment percentage	28.60%	28.60%
Poseidon
Description Of Business And Basis Of Presentation [Line Items]
Equity method investment percentage	36.00%	36.00%
Bengal
Description Of Business And Basis Of Presentation [Line Items]
Equity method investment percentage	49.00%	49.00%