Equity - Private Placement (Details) - USD ($) $ / shares in Units, $ in Millions					3 Months Ended	12 Months Ended
	Jun. 09, 2016	May 23, 2016	Mar. 29, 2016	May 18, 2015	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Units issued in connection with private placement (in units)						765,307	7,849,294
Net proceeds from private placement						$ 0.0	$ 297.4	$ 0.0
Consideration for units issued in connection with private placement						$ 9.8	$ 6.1	$ 0.0
Aggregate percentage of general partner interest						2.00%
Common Units
Class of Stock [Line Items]
Units issued in connection with private placement (in units)				7,692,308
Net proceeds from private placement				$ 297.4
Gross proceed issuance of private placement offering				$ 300.0
Common units per share (in units per share)				$ 39.00
Placement fees				$ 2.6
General Partner
Class of Stock [Line Items]
Units issued in connection with private placement (in units)				156,986	15,307	15,307	156,986
Consideration for units issued in connection with private placement	$ 1.1		$ 8.2	$ 6.1	$ 0.5
May 2016 Acquisition
Class of Stock [Line Items]
Consideration for units issued in connection with private placement		$ 7.1
Shell Pipeline Company L P | Common Units
Class of Stock [Line Items]
Units issued in connection with private placement (in units)						0	0
Shell Pipeline Company L P | May 2016 Acquisition | General Partner
Class of Stock [Line Items]
Aggregate percentage of general partner interest						2.00%