Acquisitions - Schedule of Book Value of Net Assets Under Common Control (Details) - USD ($) $ in Millions		Nov. 17, 2015	May. 18, 2015
Pecten
Business Acquisition [Line Items]
Property, plant and equipment, net	[1]	$ 95.2
Asset retirement obligation	[2]	(1.3)
Book value of net assets acquired		$ 93.9
Zydeco
Business Acquisition [Line Items]
Other assets	[3]		$ 2.5
Partners' capital	[4]		52.9
Book value of net assets acquired			$ 55.4

[1] Historical carrying value of property, plant and equipment, net contributed by SPLC.

[2] Historical carrying value of asset retirement obligation assumed by the Partnership.

[3] Book value of 1.388% additional interest in Colonial contributed by SPLC.

[4] Book value of 19.5% additional interest in Zydeco from SPLC’s noncontrolling interest.