The amount of assets representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognised. [Refer: Business combinations [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2017-01-01
-Paragraph B67
-Subparagraph d
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-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 36
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-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=36&date=2017-03-01&anchor=para_134_a&doctype=Standard
-URIDate 2017-03-09

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 36
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-URIDate 2017-03-09

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Goodwill - Schedule of Goodwill Allocated (Detail) - CAD CAD in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of goodwill allocated [line items]
Goodwill	CAD 1,556.6	CAD 1,828.1	CAD 966.5
Consulting Services Canada [member]
Disclosure of goodwill allocated [line items]
Goodwill	337.8	337.6
Consulting Services United States [member]
Disclosure of goodwill allocated [line items]
Goodwill	917.7	1,073.2
Consulting Services Global [member]
Disclosure of goodwill allocated [line items]
Goodwill	183.2	287.9
Construction Services [member]
Disclosure of goodwill allocated [line items]
Goodwill	CAD 117.9	CAD 129.4