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Revenue - Disaggregation of revenue (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 410,061	$ 292,557
Time-and-materials
Disaggregation of Revenue [Line Items]
Revenue	151,796	97,588
Unit-price
Disaggregation of Revenue [Line Items]
Revenue	253,277	191,041
Cost-plus
Disaggregation of Revenue [Line Items]
Revenue	4,988	3,928
Construction services
Disaggregation of Revenue [Line Items]
Revenue	42,481	21,710
Operations support services
Disaggregation of Revenue [Line Items]
Revenue	367,580	270,847
Cost-to-cost percent complete
Disaggregation of Revenue [Line Items]
Revenue	186,741	125,716
As-invoiced
Disaggregation of Revenue [Line Items]
Revenue	$ 223,320	$ 166,841

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- Definition

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.

+ References

No definition available.

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- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

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