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Other assets - Deferred financing costs (Details) (CAD) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Deferred financing costs [Abstract]
Cost	15,522us-gaap_DeferredFinanceCostsGross	15,536us-gaap_DeferredFinanceCostsGross
Accumulated Amortization	13,317us-gaap_AccumulatedAmortizationDeferredFinanceCosts	11,723us-gaap_AccumulatedAmortizationDeferredFinanceCosts
Net Book Value	2,205us-gaap_DeferredFinanceCostsNet	3,813us-gaap_DeferredFinanceCostsNet
Amortization of deferred financing costs	1,594us-gaap_AmortizationOfFinancingCosts	4,326us-gaap_AmortizationOfFinancingCosts
Interest expense
Deferred financing costs [Abstract]
Amortization of deferred financing costs	1,594us-gaap_AmortizationOfFinancingCosts / us-gaap_IncomeStatementLocationAxis = us-gaap_InterestExpenseMember	4,326us-gaap_AmortizationOfFinancingCosts / us-gaap_IncomeStatementLocationAxis = us-gaap_InterestExpenseMember
Revolving Facilities | Credit facilities
Deferred financing costs [Abstract]
Cost	6,878us-gaap_DeferredFinanceCostsGross / us-gaap_DebtInstrumentAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember	6,881us-gaap_DeferredFinanceCostsGross / us-gaap_DebtInstrumentAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember
Accumulated Amortization	6,347us-gaap_AccumulatedAmortizationDeferredFinanceCosts / us-gaap_DebtInstrumentAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember	5,994us-gaap_AccumulatedAmortizationDeferredFinanceCosts / us-gaap_DebtInstrumentAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember
Net Book Value	531us-gaap_DeferredFinanceCostsNet / us-gaap_DebtInstrumentAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember	887us-gaap_DeferredFinanceCostsNet / us-gaap_DebtInstrumentAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember
Financing fees incurred in connection with debt modification	87noa_DebtModificationCosts / us-gaap_DebtInstrumentAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember	1,020noa_DebtModificationCosts / us-gaap_DebtInstrumentAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember
Prior period change in financing fees	90noa_DebtModificationCostsPriorFiscalYearAdjustment / us-gaap_DebtInstrumentAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember
Series 1 Debentures | Corporate debentures
Deferred financing costs [Abstract]
Cost	8,644us-gaap_DeferredFinanceCostsGross / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember	8,655us-gaap_DeferredFinanceCostsGross / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember
Accumulated Amortization	6,970us-gaap_AccumulatedAmortizationDeferredFinanceCosts / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember	5,729us-gaap_AccumulatedAmortizationDeferredFinanceCosts / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember
Net Book Value	1,674us-gaap_DeferredFinanceCostsNet / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember	2,926us-gaap_DeferredFinanceCostsNet / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember
Financing fees incurred in connection with debt issuance	0us-gaap_DebtIssuanceCosts / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember	1,769us-gaap_DebtIssuanceCosts / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember
Prior year change in estimated financing fees	11noa_DebtModificationCostsEstimatedFinancingFeesPriorYearAdjustment / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember
Unamortized deferred financing costs expensed upon redemption of notes	534us-gaap_WriteOffOfDeferredDebtIssuanceCost / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember	2,737us-gaap_WriteOffOfDeferredDebtIssuanceCost / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember

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- Definition

Debt Modification Costs

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Debt Modification Costs, Estimated Financing Fees, Prior Year Adjustment

+ References

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Debt Modification Costs, Prior Fiscal Year Adjustment

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- Definition

For an unclassified balance sheet, the accumulated amortization, as of the reporting date, representing the periodic charge to earnings of deferred costs which are associated with debt obligations existing as of the end of the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

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- Definition

Amount of noncash expense included in interest expense to issue debt and obtain financing associated with the related debt instruments. Alternate captions include noncash interest expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Section 45

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Amount of debt issuance costs (for example, but not limited to, legal, accounting, broker, and regulatory fees).

+ References

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For an unclassified balance sheet, the amount as of the balance sheet date of capitalized costs associated with the issuance of debt instruments (for example, legal, accounting, underwriting, printing, and registration costs) that will be charged against earnings over the life of the debt instruments to which such costs pertain. Such amount is before the consideration of accumulated amortization.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Topic 835

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For an unclassified balance sheet, the carrying amount (net of accumulated amortization) as of the balance sheet date of capitalized costs associated with the issuance of debt instruments (for example, legal, accounting, underwriting, printing, and registration costs) that will be charged against earnings over the life of the debt instruments to which such costs pertain.

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Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

+ References

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-Publisher FASB

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