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Stock-based compensation - Textuals (Details) (CAD)
In Thousands, except Share data, unless otherwise specified
12 Months Ended 0 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Sep. 22, 2010
Jul. 01, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Proceeds from stock options exercised 2,807us-gaap_ProceedsFromStockOptionsExercised 1,175us-gaap_ProceedsFromStockOptionsExercised    
Shares exercised and settled during period   295,230us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised    
Share option plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number shares acquired per each option exercised 1noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNumberOfCommonSharesAwardedPerEachOptionExercised
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
     
Stock options annual vesting percentage 20.00%noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAnnualVestingPercentage
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
     
Proceeds from stock options exercised 1,348us-gaap_ProceedsFromStockOptionsExercised
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
1,175us-gaap_ProceedsFromStockOptionsExercised
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
   
Total intrinsic value of options exercised 1,711us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
524us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
   
Options outstanding, weighted average remaining life 6 years 1 month 6 years 11 months    
Fair value of options vested during the year 983us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
1,278us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
   
Number of options exercisable 824,720us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
892,700us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
   
Options exercisable, weighted average exercise price 8.41us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
8.00us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
   
Total compensation costs related to non-vested awards not yet recognized 1,223us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
1,762us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
   
Shares exercised and settled during period 385,880us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
[1] 295,230us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_PlanNameAxis
= noa_ShareOptionPlanMember
[1]    
Share option plan | Stock options        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Years from grant date stock options expire 10 years      
Total compensation costs related to non-vested awards not yet recognized, weighted average recognition period 2 years 6 months 3 years 2 months 12 days    
Senior executive stock option plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Proceeds from stock options exercised 1,459us-gaap_ProceedsFromStockOptionsExercised
/ us-gaap_PlanNameAxis
= noa_SeniorExecutiveStockOptionPlanMember
0us-gaap_ProceedsFromStockOptionsExercised
/ us-gaap_PlanNameAxis
= noa_SeniorExecutiveStockOptionPlanMember
   
Total intrinsic value of options exercised 935us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
/ us-gaap_PlanNameAxis
= noa_SeniorExecutiveStockOptionPlanMember
0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
/ us-gaap_PlanNameAxis
= noa_SeniorExecutiveStockOptionPlanMember
   
Stock options reclassified from equity to a long-term liability     550,000noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesOptionsReclassifiedFromEquityToLongTermLiabilities
/ us-gaap_PlanNameAxis
= noa_SeniorExecutiveStockOptionPlanMember
 
Shares exercised and settled during period 291,800us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_PlanNameAxis
= noa_SeniorExecutiveStockOptionPlanMember
0us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_PlanNameAxis
= noa_SeniorExecutiveStockOptionPlanMember
   
Senior executive stock option plan | Stock options        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Current portion of award obligation 22us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= noa_SeniorExecutiveStockOptionPlanMember
0us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= noa_SeniorExecutiveStockOptionPlanMember
   
Non-current portion of award obligation 0us-gaap_DeferredCompensationSharebasedArrangementsLiabilityClassifiedNoncurrent
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= noa_SeniorExecutiveStockOptionPlanMember
940us-gaap_DeferredCompensationSharebasedArrangementsLiabilityClassifiedNoncurrent
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
/ us-gaap_PlanNameAxis
= noa_SeniorExecutiveStockOptionPlanMember
   
Liability classified restricted share unit plan | Restricted share units (RSUs)        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Service period of award subsequent to year of grant 2 years      
Award vesting period 3 years      
Award units settled during the period (units) 350,271us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedRestrictedShareUnitPlanMember
154,330us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedRestrictedShareUnitPlanMember
   
Award units settled during the period 2,678us-gaap_EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedRestrictedShareUnitPlanMember
727us-gaap_EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedRestrictedShareUnitPlanMember
   
Weighted average remaining contractual life of award 0 years 9 months 1 year 4 months    
Fair market value (CAD per share) 3.78noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingFairValuePerShare
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedRestrictedShareUnitPlanMember
6.24noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingFairValuePerShare
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedRestrictedShareUnitPlanMember
   
Total unrecognized compensation costs related to non-vested share-based payment arrangements 641us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedRestrictedShareUnitPlanMember
2,958us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedRestrictedShareUnitPlanMember
   
Liability classified restricted share unit plan | Restricted share units (RSUs) | Accrued liabilities        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Current portion of award obligation 1,009us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_AccruedLiabilitiesMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedRestrictedShareUnitPlanMember
1,933us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_AccruedLiabilitiesMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedRestrictedShareUnitPlanMember
   
Liability classified restricted share unit plan | Restricted share units (RSUs) | Other long-term liabilities        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Non-current portion of award obligation 770us-gaap_DeferredCompensationSharebasedArrangementsLiabilityClassifiedNoncurrent
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_OtherLiabilitiesMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedRestrictedShareUnitPlanMember
1,734us-gaap_DeferredCompensationSharebasedArrangementsLiabilityClassifiedNoncurrent
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_OtherLiabilitiesMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedRestrictedShareUnitPlanMember
   
Equity classified restricted share unit plan | Restricted share units (RSUs)        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Award units settled during the period (units) 605us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_PlanNameAxis
= noa_EquityClassifiedRestrictedShareUnitPlanMember
0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_PlanNameAxis
= noa_EquityClassifiedRestrictedShareUnitPlanMember
   
Weighted average remaining contractual life of award 2 years 4 months      
Total unrecognized compensation costs related to non-vested share-based payment arrangements 1,276us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_PlanNameAxis
= noa_EquityClassifiedRestrictedShareUnitPlanMember
0us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
/ us-gaap_PlanNameAxis
= noa_EquityClassifiedRestrictedShareUnitPlanMember
   
Performance restricted share unit plan | Performance restricted share units (PSUs)        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total compensation costs related to non-vested awards not yet recognized 468us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
/ us-gaap_AwardTypeAxis
= noa_PerformanceRestrictedShareUnitsMember
/ us-gaap_PlanNameAxis
= noa_PerformanceRestrictedShareUnitPlanMember
     
Total compensation costs related to non-vested awards not yet recognized, weighted average recognition period 2 years 6 months      
Award vesting period       3 years
Fair value of awards granted on July 1, 2014       563noa_SharebasedCompensationArrangementbySharebasedPaymentAwardOtherThanOptionsGrantsinPeriodAggregateFairValue
/ us-gaap_AwardTypeAxis
= noa_PerformanceRestrictedShareUnitsMember
/ us-gaap_PlanNameAxis
= noa_PerformanceRestrictedShareUnitPlanMember
Deferred share unit plan | Deferred stock units (DSUs)        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Percentage of non-officer directors' fixed remuneration in the form of DDSUs (50% or more) 50.00%noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPercentageOfNonOfficerDirectorCompensationPaidInFormOfDeferredStockUnits
/ us-gaap_AwardTypeAxis
= noa_DeferredStockUnitsMember
/ us-gaap_PlanNameAxis
= noa_DeferredShareUnitPlanMember
     
Liability classified deferred stock unit plan | Deferred stock units (DSUs)        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Award units settled during the period (units) 63,886us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= noa_DeferredStockUnitsMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedDeferredStockUnitPlanMember
179,831us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= noa_DeferredStockUnitsMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedDeferredStockUnitPlanMember
   
Award units settled during the period 557us-gaap_EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards
/ us-gaap_AwardTypeAxis
= noa_DeferredStockUnitsMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedDeferredStockUnitPlanMember
968us-gaap_EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards
/ us-gaap_AwardTypeAxis
= noa_DeferredStockUnitsMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedDeferredStockUnitPlanMember
   
Fair market value (CAD per share) 3.78noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingFairValuePerShare
/ us-gaap_AwardTypeAxis
= noa_DeferredStockUnitsMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedDeferredStockUnitPlanMember
6.24noa_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingFairValuePerShare
/ us-gaap_AwardTypeAxis
= noa_DeferredStockUnitsMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedDeferredStockUnitPlanMember
   
Liability classified deferred stock unit plan | Deferred stock units (DSUs) | Accrued liabilities        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Current portion of award obligation 408us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent
/ us-gaap_AwardTypeAxis
= noa_DeferredStockUnitsMember
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_AccruedLiabilitiesMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedDeferredStockUnitPlanMember
0us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent
/ us-gaap_AwardTypeAxis
= noa_DeferredStockUnitsMember
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_AccruedLiabilitiesMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedDeferredStockUnitPlanMember
   
Liability classified deferred stock unit plan | Deferred stock units (DSUs) | Other long-term liabilities        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Non-current portion of award obligation 1,597us-gaap_DeferredCompensationSharebasedArrangementsLiabilityClassifiedNoncurrent
/ us-gaap_AwardTypeAxis
= noa_DeferredStockUnitsMember
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_OtherLiabilitiesMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedDeferredStockUnitPlanMember
3,662us-gaap_DeferredCompensationSharebasedArrangementsLiabilityClassifiedNoncurrent
/ us-gaap_AwardTypeAxis
= noa_DeferredStockUnitsMember
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_OtherLiabilitiesMember
/ us-gaap_PlanNameAxis
= noa_LiabilityClassifiedDeferredStockUnitPlanMember
   
[1] All stock options exercised resulted in new common shares being issued (note 17(a))