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v2.4.1.9

Long term debt - Credit facilities (Details) (CAD) | 0 Months Ended |  |
--- | --- | --- | ---
Sep. 10, 2014 | Dec. 31, 2013 | Dec. 31, 2014 tranche
Line of Credit Facility [Line Items] |  |  |
Covenant terms, maximum senior leverage ratio | 2.50 noa_LineofCreditFacilityCovenantTermsMaximumSeniorLeverageRatio | 2.00 noa_LineofCreditFacilityCovenantTermsMaximumSeniorLeverageRatio |
Capital lease debt |  |  |
Line of Credit Facility [Line Items] |  |  |
Increase in borrowing capacity, amount | 15,000,000.0 noa_LineofCreditFacilityMaximumBorrowingCapacityIncrease / us-gaap_CreditFacilityAxis = us-gaap_CapitalLeaseObligationsMember |  |
Maximum borrowing capacity of credit facility | 90,000,000.0 us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_CapitalLeaseObligationsMember |  |
Revolving Facility |  |  |
Line of Credit Facility [Line Items] |  |  |
Maximum borrowing capacity of credit facility |  |  | 85,000,000 us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember
Number of tranches |  |  | 2 noa_LineofCreditFacilityNumberofTranches / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember
Unused borrowing availability under the revolving facility |  | 60,000,000 us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember | 54,500,000 us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember
Tranche A | Revolving Facility |  |  |
Line of Credit Facility [Line Items] |  |  |
Maximum borrowing capacity of credit facility |  |  | 60,000,000 us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_DebtInstrumentAxis = noa_TrancheAMember
Outstanding borrowings under credit facilities |  | 0 us-gaap_LineOfCreditFacilityAmountOutstanding / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_DebtInstrumentAxis = noa_TrancheAMember | 5,500,000 us-gaap_LineOfCreditFacilityAmountOutstanding / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_DebtInstrumentAxis = noa_TrancheAMember
Tranche B | Revolving Facility |  |  |
Line of Credit Facility [Line Items] |  |  |
Unused borrowing availability under the revolving facility |  |  | 25,000,000 us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_DebtInstrumentAxis = noa_TrancheBMember
Tranche B | Letters of credit |  |  |
Line of Credit Facility [Line Items] |  |  |
Outstanding borrowings under credit facilities |  | 3,100,000 us-gaap_LineOfCreditFacilityAmountOutstanding / us-gaap_CreditFacilityAxis = us-gaap_LetterOfCreditMember / us-gaap_DebtInstrumentAxis = noa_TrancheBMember | 5,100,000 us-gaap_LineOfCreditFacilityAmountOutstanding / us-gaap_CreditFacilityAxis = us-gaap_LetterOfCreditMember / us-gaap_DebtInstrumentAxis = noa_TrancheBMember
Corporate debentures | Series 1 Debentures |  |  |
Line of Credit Facility [Line Items] |  |  |
Approved redemption amount | 20,000,000 noa_ExtinguishmentofDebtApprovedRedemptionAmount / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember |  |

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- Definition Extinguishment of Debt, Approved Redemption Amount + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- Definition Line of Credit Facility, Covenant Terms, Maximum Senior Leverage Ratio + References No definition available. + Details
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- Definition Line of Credit Facility, Maximum Borrowing Capacity, Increase + References No definition available. + Details
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Namespace Prefix: | noa_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Line of Credit Facility, Number of Tranches + References No definition available. + Details
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- Definition Amount borrowed under the credit facility as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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- Details
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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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- Definition Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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- Details
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- Details
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- Details
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- Details
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