Acquisitions and Divestiture - Statement of Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Revenue
Transportation, terminaling and storage services - third parties											$ 251.5		$ 268.4
Transportation, terminaling and storage services - related parties											188.3		217.1
Lease revenue - related parties									$ 56.3		13.1	[1]	0.0	[1]
Total revenue	$ 126.8	$ 121.8	$ 112.4	$ 109.1	$ 115.1	$ 107.7	$ 112.9	$ 117.2	470.1		452.9	[1]	485.5	[1]
Operating Costs and Expenses [Abstract]
Operations and maintenance - third parties									104.1		76.9	[1]	84.8	[1]
Operations and maintenance - related parties									45.6		40.0	[1]	39.0	[1]
Loss on disposition of fixed asset									0.1		0.2	[1],[2]	0.3	[1],[2]
General and administrative - third parties									10.1		9.7	[1]	13.4	[1]
General and administrative - related parties									47.7		43.7	[1]	42.5	[1]
Depreciation, amortization and accretion									45.0		43.1	[1],[2]	37.9	[1],[2]
Property and other taxes									17.4		15.8	[1]	15.0	[1]
Total costs and expenses									270.0		229.4	[1]	232.9	[1]
Operating income									200.1		223.5	[1]	252.6	[1]
Income from equity investments									186.6		138.1	[1]	104.7	[1]
Dividend income from cost investments									37.4		28.3	[1]	20.6	[1]
Other loss									0.0		(0.1)	[1]	0.3	[1]
Investment, dividend and other loss											166.3		125.6
Interest expense, net									32.2		12.3	[1]	4.3	[1]
Income before income taxes	102.6	99.5	91.7	98.1	95.5	84.4	98.6	99.0	391.9		377.5	[1]	373.9	[1]
Income tax expense (benefit)									0.1		0.0	[1]	(0.1)	[1]
Net income	102.5	99.5	91.7	98.1	95.5	84.4	98.6	99.0	391.8	[3]	377.5	[1],[2],[3]	374.0	[1],[2],[3]
Less: Net income attributable to the Parent									77.3		102.3	[1]	133.8	[1]
Less: Net income attributable to noncontrolling interests									19.2		30.3	[1]	73.1	[1]
Net income attributable to the Partnership	$ 86.4	$ 72.6	$ 65.5	$ 70.8	$ 69.5	$ 56.3	$ 63.8	$ 55.3	$ 295.3		244.9	[1]	167.1	[1]
Scenario, Previously Reported
Revenue
Transportation, terminaling and storage services - third parties											201.5		222.8
Transportation, terminaling and storage services - related parties											89.8		103.7
Lease revenue - related parties											0.0
Total revenue											291.3		326.5
Operating Costs and Expenses [Abstract]
Operations and maintenance - third parties											46.9		46.3
Operations and maintenance - related parties											20.7		18.5
Loss on disposition of fixed asset											0.1		0.0
General and administrative - third parties											8.1		10.2
General and administrative - related parties											23.1		24.6
Depreciation, amortization and accretion											23.7		21.6
Property and other taxes											8.2		7.5
Total costs and expenses											130.8		128.7
Operating income											160.5		197.8
Income from equity investments											101.1		70.1
Dividend income from cost investments											16.1		9.2
Other loss											0.0		0.0
Investment, dividend and other loss											117.2		79.3
Interest expense, net											12.3		4.3
Income before income taxes											265.4		272.8
Income tax expense (benefit)											0.0		(0.1)
Net income											265.4		272.9
Less: Net income attributable to the Parent											0.0		39.3
Less: Net income attributable to noncontrolling interests											20.5		66.5
Net income attributable to the Partnership											244.9		167.1
May 2017 Acquisition | Scenario, Previously Reported
Revenue
Transportation, terminaling and storage services - third parties											33.0		29.0
Transportation, terminaling and storage services - related parties											26.8		34.2
Lease revenue - related parties											0.0
Total revenue											59.8		63.2
Operating Costs and Expenses [Abstract]
Operations and maintenance - third parties											13.3		18.9
Operations and maintenance - related parties											8.9		8.3
Loss on disposition of fixed asset											0.0		0.0
General and administrative - third parties											0.3		1.8
General and administrative - related parties											7.5		5.5
Depreciation, amortization and accretion											12.9		10.2
Property and other taxes											5.2		5.0
Total costs and expenses											48.1		49.7
Operating income											11.7		13.5
Income from equity investments											0.0		0.0
Dividend income from cost investments											0.0		0.0
Other loss											0.0		0.3
Investment, dividend and other loss											0.0		0.3
Interest expense, net											0.0		0.0
Income before income taxes											11.7		13.8
Income tax expense (benefit)											0.0		0.0
Net income											11.7		13.8
Less: Net income attributable to the Parent											11.7		13.8
Less: Net income attributable to noncontrolling interests											0.0		0.0
Net income attributable to the Partnership											0.0		0.0
December 2017 Acquisition | Scenario, Previously Reported
Revenue
Transportation, terminaling and storage services - third parties											17.0		16.6
Transportation, terminaling and storage services - related parties											71.7		79.2
Lease revenue - related parties											13.1
Total revenue											101.8		95.8
Operating Costs and Expenses [Abstract]
Operations and maintenance - third parties											16.7		19.6
Operations and maintenance - related parties											10.4		12.2
Loss on disposition of fixed asset											0.1		0.3
General and administrative - third parties											1.3		1.4
General and administrative - related parties											13.1		12.4
Depreciation, amortization and accretion											6.5		6.1
Property and other taxes											2.4		2.5
Total costs and expenses											50.5		54.5
Operating income											51.3		41.3
Income from equity investments											37.0		34.6
Dividend income from cost investments											12.2		11.4
Other loss											(0.1)		0.0
Investment, dividend and other loss											49.1		46.0
Interest expense, net											0.0		0.0
Income before income taxes											100.4		87.3
Income tax expense (benefit)											0.0		0.0
Net income											100.4		87.3
Less: Net income attributable to the Parent											90.6		80.7
Less: Net income attributable to noncontrolling interests											9.8		6.6
Net income attributable to the Partnership											$ 0.0		$ 0.0

[1] The financial information presented has been retrospectively adjusted for acquisitions of businesses under common control.

[2] The financial information presented has been retrospectively adjusted for acquisitions of businesses under common control.

[3] The financial information presented has been retrospectively adjusted for acquisitions of businesses under common control.