v3.19.3.a.u2

Acquisitions and divestments - Koma Kulshan Associates (Details) $ in Millions			12 Months Ended
	Jul. 27, 2018 USD ($)	Jun. 18, 2018 USD ($) item	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Jun. 17, 2018
Asset acquisitions
Percentage of equity method ownership interest		100.00%
Equity investments in unconsolidated affiliates			$ 140.8	$ 96.6
Koma Kulshan Associates
Asset acquisitions
Percentage of equity method ownership interest		50.00%			49.75%
Equity investments in unconsolidated affiliates		$ 1.1
Number of owner parties with joint control | item		2
Concrete
Asset acquisitions
Percentage of general partner interest purchased		0.50%
Purchase price of partnership interest		$ 1.1
Koma Kulshan Associates
Asset acquisitions
Purchase price	$ 12.5
Interest acquired in the plant	100.00%
Gain recognized from step acquisition			$ 7.2
Koma Kulshan Associates
Asset acquisitions
Percentage of general partner interest purchased	50.00%
Concrete | General Partner
Asset acquisitions
Percentage of equity method ownership interest					0.50%
Concrete | Limited Partner
Asset acquisitions
Percentage of equity method ownership interest					99.00%
Concrete | Koma Kulshan Associates
Asset acquisitions
Percentage of equity method ownership interest		50.00%
Covanta
Asset acquisitions
Percentage of equity method ownership interest	50.00%
Covanta | Koma Kulshan Associates
Asset acquisitions
Purchase price	$ 12.5

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