XML 148 R120.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Net Employee Defined Benefit Liability - Summary of Quantitative Sensitivity Analyses Impact on Defined Benefit Obligation for Significant Assumptions (Detail) - CAD CAD in Millions | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Change in discount rate by 0.25% [member] |  |
Disclosure of sensitivity analysis for actuarial assumptions [Line Items] |  |
Increase | CAD (11.2) | CAD (10.5)
Decrease | 11.8 | 11.0
Change in pre-retirement inflation rate by 0.25% [member] |  |
Disclosure of sensitivity analysis for actuarial assumptions [Line Items] |  |
Increase | 3.9 | 3.5
Decrease | (3.8) | (3.3)
Change in salary growth by 0.25% [member] |  |
Disclosure of sensitivity analysis for actuarial assumptions [Line Items] |  |
Increase | 0.5 | 0.8
Decrease | (0.5) | (0.6)
Change in pension increase assumption by 0.25% [member] |  |
Disclosure of sensitivity analysis for actuarial assumptions [Line Items] |  |
Increase | 6.4 | 0.8
Decrease | (6.1) | (0.8)
Increase of one year in the life expectancy [member] |  |
Disclosure of sensitivity analysis for actuarial assumptions [Line Items] |  |
Increase | CAD 6.0 | CAD 4.6

X
- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. + References No definition available. + Details
Name: | ifrs-full_DisclosureOfSensitivityAnalysisForActuarialAssumptionsLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The increase (decrease) in a defined benefit obligation that would have been caused by a decrease in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 145 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_145_a&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleDecreaseInActuarialAssumption
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The increase (decrease) in a defined benefit obligation that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 145 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_145_a&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleIncreaseInActuarialAssumption
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=stn_ActuarialAssumptionOfDiscountRatesZeroPointTwoFivePercentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=stn_ActuarialAssumptionOfExpectedRatesOfInflationPreRetirementZeroPointTwoFivePercentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=stn_ActuarialAssumptionOfExpectedRatesOfSalaryIncreasesZeroPointTwoFivePercentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=stn_ActuarialAssumptionOfExpectedRatesOfPensionIncreasesZeroPointTwoFivePercentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=stn_ActuarialAssumptionsOfExpectedIncreaseOfOneYearInLifeExpectancyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |