Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended
	Apr. 28, 2017	Apr. 19, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	May 04, 2017
Subsequent Event [Line Items]
Distributions paid per limited partner unit (in dollars per unit)			$ 0.291	$ 0.27700	$ 0.26375	$ 0.2500	$ 0.2350	$ 0.2200
Subsequent Event
Subsequent Event [Line Items]
Distributions paid per limited partner unit (in dollars per unit)		$ 0.291
Subsequent Event | Shell Chemical LP, Shell GOM Pipeline Company LP, And SPLC
Subsequent Event [Line Items]
Acquired ownership interest									100.00%
Purchase price									$ 630.0
Subsequent Event | Zydeco
Subsequent Event [Line Items]
Transaction price	$ 21.0