Related Party Transactions - Additional Information (Details)								3 Months Ended			9 Months Ended
	Sep. 15, 2017 USD ($)	Sep. 27, 2016	Mar. 29, 2016 USD ($)	Nov. 11, 2015	Jun. 29, 2015	May 12, 2015	Nov. 03, 2014 USD ($)	Sep. 30, 2017 USD ($) credit_facility	Sep. 30, 2016 USD ($)	Mar. 31, 2016	Sep. 30, 2017 USD ($) credit_facility term		Sep. 30, 2016 USD ($)		Dec. 31, 2016	May 23, 2016	May 31, 2015
Related Party Transaction [Line Items]
Repayments of Lines of Credit											$ 265,000,000	[1]	$ 410,000,000	[2]
Reimbursement Of Cost And Expenses Incurred								$ 3,100,000			13,600,000
Aggregate liability of SPLC								10,700,000			10,700,000
Statute of limitations expirations, number of days							60 days
Revenue from related parties									$ 28,100,000				86,000,000
Gain (loss) from sale of excess allowance oil								100,000	300,000		800,000		800,000
Transportation Services
Related Party Transaction [Line Items]
Revenue from related parties								28,600,000	25,800,000		77,900,000		79,500,000
Storage Services
Related Party Transaction [Line Items]
Revenue from related parties								1,200,000	2,300,000		4,600,000		6,500,000
Transportation Services Operating Leases
Related Party Transaction [Line Items]
Revenue from related parties								$ 11,700,000	0		$ 19,400,000		0
Initial term											10 years
Number of additional terms | term											2
Additional term											5 years
Shell Treasury Center West Inc
Related Party Transaction [Line Items]
Number of revolving credit facilities | credit_facility								3			3
Zydeco, Mars, Bengal, Poseidon and Colonial
Related Party Transaction [Line Items]
Total distributions to general partners								$ 71,400,000	63,900,000		$ 249,100,000		174,800,000
SPLC
Related Party Transaction [Line Items]
General and administrative - related parties								3,400,000	2,300,000		8,400,000		7,800,000
General insurance expense								$ 2,100,000	1,200,000		$ 5,100,000		4,200,000
Five Year Revolver | Shell Treasury Center West Inc
Related Party Transaction [Line Items]
Debt instrument term	5 years		5 years					5 years		5 years	5 years
Five Year Fixed Facility | Shell Treasury Center West Inc
Related Party Transaction [Line Items]
Debt instrument term											5 years
364 Day Revolver | Shell Treasury Center West Inc
Related Party Transaction [Line Items]
Repayments of Lines of Credit			$ 137,400,000
Debt instrument term			364 days							364 days	364 days
SPLC | Zydeco Pipeline Company LLC (“Zydeco”)
Related Party Transaction [Line Items]
Noncontrolling Interest							57.00%	7.50%			7.50%				7.50%	7.50%	37.50%
Maximum
Related Party Transaction [Line Items]
Aggregate liability of SPLC							$ 15,000,000
Shell Auger and Lockport Operations
Related Party Transaction [Line Items]
Reimbursement Of Cost And Expenses Incurred									1,000,000				1,200,000
Shell Pipeline Company L P
Related Party Transaction [Line Items]
Payment of general and administrative fee							$ 8,500,000
Zydeco Pipeline Company LLC (“Zydeco”)
Related Party Transaction [Line Items]
Reimbursement Of Cost And Expenses Incurred								$ 2,200,000	100,000		$ 12,100,000		400,000
Total distributions to general partners								$ 24,100,000	$ 35,100,000		$ 105,500,000		$ 80,700,000
Revolving Credit Facility [Member] | Five Year Revolver | Shell Treasury Center West Inc
Related Party Transaction [Line Items]
Repayments of Lines of Credit	$ 265,000,000		$ 272,600,000
Debt instrument term		5 years	5 years			5 years	5 years				5 years
Revolving Credit Facility [Member] | 364 Day Revolver | Shell Treasury Center West Inc
Related Party Transaction [Line Items]
Debt instrument term				364 days	364 days						364 days

[1] The financial information for the nine months ended September 30, 2017 reflects adjustments for the acquisition of the Shell Delta,Na Kika and Refinery Gas Pipeline Operations from January 1, 2017 through May 9, 2017.

[2] Prior period financial information has been retrospectively adjusted for the acquisition of the Shell Delta, Na Kika and Refinery Gas Pipeline Operations.