Net Income Per Limited Partner Unit - Schedule of Allocation of Net Income to Arrive at Net Income Per Limited Partner Unit (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015		Sep. 30, 2016	Sep. 30, 2015
Limited Partners Capital Account [Line Items]
Net income	$ 58.8	$ 90.6	[1]	$ 193.1	$ 200.4	[1],[2]
Less: Net income attributable to Parent	0.0	16.2	[1]	0.0	39.3	[1]
Less: Net income attributable to noncontrolling interests	2.5	20.1	[1]	17.7	51.0	[1]
Net income attributable to the Partnership	56.3	54.3	[1]	175.4	110.1	[1]
Distribution declared	53.9	30.3		144.6	82.1
Income in excess of distributions	2.4	24.0		30.8	28.0
General Partner
Limited Partners Capital Account [Line Items]
Net income attributable to the Partnership	7.2	1.5		15.3	2.7
Distribution declared	7.1	1.0		14.7	2.1
Income in excess of distributions	0.1	0.5		0.6	0.6
Limited Partners' Common Units
Limited Partners Capital Account [Line Items]
Net income attributable to the Partnership	30.4	27.8		97.4	56.0
Distribution declared	29.0	15.4		79.4	41.5
Income in excess of distributions	1.4	12.4		18.0	14.5
Limited Partner's Subordinated Units
Limited Partners Capital Account [Line Items]
Net income attributable to the Partnership	18.7	25.0		62.7	51.4
Distribution declared	17.8	13.9		50.5	38.5
Income in excess of distributions	$ 0.9	$ 11.1		$ 12.2	$ 12.9

[1] (1) The 2015 financial information has been retrospectively adjusted for the acquisition of the Shell Auger and Lockport Operations.

[2] (1) The 2015 financial information has been retrospectively adjusted for the acquisition of the Shell Auger and Lockport Operations.