Agreement of Limited Partnership (Tables)

12 Months Ended

Dec. 31, 2016

Distributions Made to Members or Limited Partners [Abstract]

Summary of available cash distribution

Available Cash as summarized in the following table:

	Income and Distribution Allocation
	Target Limit		Target Increment		Common Units		Class B Common Units		General Partner(1)		Total
Minimum Quarterly Distributions	$	0.605	$	0.605	98.990	%	0.985	%	0.025	%	100.00	%
First Target	0.715		0.110		98.990	%	0.985	%	0.025	%	100.00	%
Second Target	0.825		0.110		85.859	%	0.985	%	13.156	%	100.00	%
Third Target	1.045		0.220		75.758	%	0.985	%	23.257	%	100.00	%
Final Target and Beyond	>1.045		—		50.505	%	0.985	%	48.510	%	100.00	%

Schedule of the quarterly cash distributions paid to the unitholders and the General Partner

The quarterly cash distributions to the unitholders and the General Partner declared in 2016 and 2015 are as follows:

		Common Units				Class B Common Units				General Partner		Total Distributions Declared
		Total		Per unit		Total		Per unit		Total
		(in millions, except per unit amounts)
2016
	First Quarter	$	53.3	$	2.88	$	0.9	$	4.78	$	36.0	$	90.2
	Second Quarter	28.0		1.51		0.4		2.09		11.1		39.5
	Third Quarter	47.7		2.58		0.7		4.17		30.4		78.8
	Fourth Quarter	32.7		1.77		0.5		2.60		15.8		49.0
2015
	First Quarter	$	46.3	$	2.50	$	0.7	$	4.03	$	29.1	$	76.1
	Second Quarter	38.5		2.08		0.6		3.20		21.3		60.4
	Third Quarter	43.6		2.36		0.7		3.74		26.5		70.8
	Fourth Quarter	52.0		2.81		0.9		4.64		34.6		87.5