Segmented Information - Schedule of Gross Revenue by Services (Detail) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Disclosure of products and services [line items]
Gross revenue	$ 4,283.8	$ 4,028.7
Consulting Services [member] \| Buildings Services [member]
Disclosure of products and services [line items]
Gross revenue	944.5	898.1
Consulting Services [member] \| Energy and Resources Services [member]
Disclosure of products and services [line items]
Gross revenue	591.7	479.2
Consulting Services [member] \| Environmental Services [member]
Disclosure of products and services [line items]
Gross revenue	682.8	678.1
Consulting Services [member] \| Infrastructure [member]
Disclosure of products and services [line items]
Gross revenue	1,157.6	1,090.4
Consulting Services [member] \| Water Services [member]
Disclosure of products and services [line items]
Gross revenue	$ 907.2	$ 882.9

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