Commitments and Contingencies (Details)	Jul. 01, 2019	Sep. 01, 2016
Commitments and Contingencies Disclosure [Abstract]
Traffic rate increase	4.30%
Initial term of contract		10 years
Renewal term		1 year

Lessee Leasing Arrangements, Capital Lease, Term of Contract

No definition available.

Name:	shlx_LesseeLeasingArrangementsCapitalLeaseTermofContract
Namespace Prefix:	shlx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration