Related Party Transactions - Schedule of Condensed Combined Statement of Operations (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2017		Jun. 30, 2016		Jun. 30, 2017		Jun. 30, 2016
Related Party Transaction [Line Items]
Operations and maintenance – related parties	$ 7.1	[1]	$ 7.4	[2]	$ 18.2	[1]	$ 15.1	[2]
General and administrative – related parties	8.2	[1]	7.6	[2]	16.6	[1]	14.9	[2]
Management Agreement
Related Party Transaction [Line Items]
Payment for general administrative services	2.0		1.9		4.0		3.9
Omnibus Agreement
Related Party Transaction [Line Items]
Payment for general administrative services	$ 2.1		$ 2.1		$ 4.2		$ 4.2

[1] The 2017 financial information 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.