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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	2.50noa_LineofCreditFacilityCovenantTermsMaximumSeniorLeverageRatio	2.00noa_LineofCreditFacilityCovenantTermsMaximumSeniorLeverageRatio
Capital lease debt
Line of Credit Facility [Line Items]
Increase in borrowing capacity, amount	15,000,000.0noa_LineofCreditFacilityMaximumBorrowingCapacityIncrease / us-gaap_CreditFacilityAxis = us-gaap_CapitalLeaseObligationsMember
Maximum borrowing capacity of credit facility	90,000,000.0us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_CapitalLeaseObligationsMember
Revolving Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity of credit facility			85,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember
Number of tranches			2noa_LineofCreditFacilityNumberofTranches / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember
Unused borrowing availability under the revolving facility		60,000,000us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember	54,500,000us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember
Tranche A | Revolving Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity of credit facility			60,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_DebtInstrumentAxis = noa_TrancheAMember
Outstanding borrowings under credit facilities		0us-gaap_LineOfCreditFacilityAmountOutstanding / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_DebtInstrumentAxis = noa_TrancheAMember	5,500,000us-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			25,000,000us-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		3,100,000us-gaap_LineOfCreditFacilityAmountOutstanding / us-gaap_CreditFacilityAxis = us-gaap_LetterOfCreditMember / us-gaap_DebtInstrumentAxis = noa_TrancheBMember	5,100,000us-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	20,000,000noa_ExtinguishmentofDebtApprovedRedemptionAmount / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember

X

- Definition

Extinguishment of Debt, Approved Redemption Amount

+ References

No definition available.

+ Details

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Namespace Prefix:	noa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Line of Credit Facility, Covenant Terms, Maximum Senior Leverage Ratio

+ References

No definition available.

+ Details

Name:	noa_LineofCreditFacilityCovenantTermsMaximumSeniorLeverageRatio
Namespace Prefix:	noa_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- 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

X

- Definition

Line of Credit Facility, Number of Tranches

+ References

No definition available.

+ Details

Name:	noa_LineofCreditFacilityNumberofTranches
Namespace Prefix:	noa_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- 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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Namespace Prefix:	us-gaap_
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Balance Type:	credit
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- Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- 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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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- 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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Period Type:

X

- Details

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X

- Details

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- Details

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