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Revenue - Disaggregation of revenue (Details) - CAD ($) $ in Thousands | 12 Months Ended
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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 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 + Details
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