Revenue and segmented information - Primary sources of revenue (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Revenue and segmented information
Construction contracts	$ 1,183.2	$ 1,342.4
Services contracts	448.0	215.1
Total revenue	$ 1,631.2	$ 1,557.5

The income arising in the course of an entity's ordinary activities. Income is increases in economic benefits during the accounting period in the form of inflows or enhancements of assets or decreases of liabilities that result in an increase in equity, other than those relating to contributions from equity participants.

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+ Details