Amount of operation and maintenance contract purchased.

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The period over which the contractual agreement is or will be in force.

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Percentage of general partner interest purchased in limited partnership.

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Number of owner parties that have joint control and substantive participating rights through the structure of its partnership agreement.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Percentage investment held by members or limited partners of limited liability company (LLC) or limited partnership (LP).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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-Name Accounting Standards Codification
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The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

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Cash outflow related to the acquisition or continued holding of limited partnership interests held for investment purposes.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Equity method investments in unconsolidated affiliates - acquisitions (Details) $ in Millions				6 Months Ended
	Jul. 27, 2018 USD ($)	Jun. 18, 2018 USD ($)	Jul. 27, 2017	Jun. 30, 2018 USD ($) item	Jun. 17, 2018	Dec. 31, 2017 USD ($)
Equity method investments
Investment in equity method project				$ 1.1
Equity investments in unconsolidated affiliates				$ 160.9		$ 163.7
Koma
Equity method investments
Percentage of limited partner interest held	100.00%
Percentage of equity method ownership interest		50.00%		50.00%	49.75%
Equity investments in unconsolidated affiliates		$ 1.1
Number of owner parties with joint control \| item				2
Contract term			19 years
Concrete \| General Partner
Equity method investments
Percentage of general partner interest purchased		0.50%
Purchase price of partnership interest		$ 1.1
Concrete
Equity method investments
Percentage of equity method ownership interest		100.00%
Concrete \| General Partner
Equity method investments
Percentage of equity method ownership interest					0.50%
Concrete \| Limited Partner
Equity method investments
Percentage of equity method ownership interest					99.00%
Concrete \| Koma
Equity method investments
Percentage of limited partner interest held		50.00%
Covanta
Equity method investments
Amount of operations and maintenance contract purchased	$ 0.3
Covanta \| Koma
Equity method investments
Percentage of general partner interest purchased	50.00%
Purchase price of partnership interest	$ 11.8
Total cash paid to acquire business	$ 12.1