Acquisitions and Divestiture - Book Value of Net Assets Acquired (Details) - USD ($) $ in Millions	Dec. 01, 2017	May 23, 2016	May 18, 2015	May 10, 2017	Dec. 27, 2016	Oct. 03, 2016	Nov. 17, 2015
December 2017 Acquisition
Business Acquisition [Line Items]
Cost investment	$ 22.3
Equity method investments	76.1
Partners' capital	3.2
Property, plant and equipment, net	118.2
Book value of net assets	$ 219.8
Explorer
Business Acquisition [Line Items]
Voting interest acquired	10.00%
Mars Oil Pipeline Company LLC (“Mars”)
Business Acquisition [Line Items]
Book value of net assets						$ 51.3
Voting interest acquired	22.90%					20.00%
LOCAP LLC (“LOCAP”)
Business Acquisition [Line Items]
Voting interest acquired	41.48%
Shell Oil Products US (SOPUS)
Business Acquisition [Line Items]
Voting interest acquired	100.00%
Odyssey Pipeline L.L.C. (“Odyssey”)
Business Acquisition [Line Items]
Voting interest acquired	22.00%
Odyssey Pipeline L.L.C. (“Odyssey”) | Odyssey Pipeline L.L.C. (“Odyssey”)
Business Acquisition [Line Items]
Book value of net assets						$ 3.0
Voting interest acquired						49.00%
Delta
Business Acquisition [Line Items]
Book value of net assets				$ 40.1
Na Kika
Business Acquisition [Line Items]
Book value of net assets				26.0
Refinery Gas Pipeline
Business Acquisition [Line Items]
Book value of net assets				134.6
May 2017 Acquisition
Business Acquisition [Line Items]
Book value of net assets				$ 200.7
Voting interest acquired				100.00%
December 2016 Acquisition
Business Acquisition [Line Items]
Cost investment					$ 2.1
Equity method investments					39.9
Book value of net assets					42.0
December 2016 Acquisition | Cleopatra
Business Acquisition [Line Items]
Book value of net assets					$ 2.1
Voting interest acquired					1.00%
December 2016 Acquisition | Endymion Oil Pipeline Company, LLC (“Endymion”)
Business Acquisition [Line Items]
Book value of net assets					$ 20.8
Voting interest acquired					10.00%
December 2016 Acquisition | Proteus Oil Pipeline Company, LLC (“Proteus”)
Business Acquisition [Line Items]
Book value of net assets					$ 19.1
Voting interest acquired					10.00%
October 2016 Acquisitions
Business Acquisition [Line Items]
Equity method investments						$ 54.3
Book value of net assets						$ 54.3
May 2016 Acquisition
Business Acquisition [Line Items]
Cost investment		$ 5.2
Equity method investments		1.5
Partners' capital		87.0
Book value of net assets		$ 93.7
Colonial
Business Acquisition [Line Items]
Voting interest acquired		3.00%
Additional minority interest ownership percentage by parent acquired			1.388%
Bengal Pipeline Company LLC (“Bengal”)
Business Acquisition [Line Items]
Voting interest acquired		1.00%
Zydeco Pipeline Company LLC (“Zydeco”)
Business Acquisition [Line Items]
Voting interest acquired		30.00%
Additional minority interest ownership percentage by parent acquired			19.50%
November 2015 Acquisition
Business Acquisition [Line Items]
Property, plant and equipment, net							$ 95.2
Asset retirement obligation							(1.3)
Book value of net assets							$ 93.9
May 2015 Acquisition
Business Acquisition [Line Items]
Cost investment			$ 2.5
Partners' capital			52.9
Book value of net assets			$ 55.4