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Long term debt - Series 1 Debentures (Details) (CAD) | 0 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Dec. 22, 2014 | Apr. 08, 2014 | Feb. 28, 2014 | Dec. 31, 2014 | Dec. 31, 2013 | Apr. 07, 2010
Debt Instrument [Line Items] |  |  |  |  |  |
Gain (loss) on debt extinguishment |  |  |  | (54,000)us-gaap_GainsLossesOnExtinguishmentOfDebt | (6,476,000)us-gaap_GainsLossesOnExtinguishmentOfDebt |
Corporate debentures | Series 1 Debentures |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Face amount of long term debt |  |  |  |  |  | 225,000,000 us-gaap_DebtInstrumentFaceAmount / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember
Stated interest rate on long term debt |  |  |  |  |  | 9.125%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember
Redemption price as a percentage of the principal amount |  |  | 103.042%us-gaap_DebtInstrumentRedemptionPricePercentage / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember |  |  |
Redemption premium upon a change of control |  |  |  |  |  | 101.00%noa_DebtInstrumentRedemptionPremiumUponChangeofControlPercentage / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember
Amount of debt elected to be redeemed |  |  | 10,000,000 noa_ExtinguishmentofDebtAmountElectedtobeRedeemed / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember |  |  |
Redemption amount of Series 1 Debentures | 6,300,000 us-gaap_ExtinguishmentOfDebtAmount / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember | 10,000,000 us-gaap_ExtinguishmentOfDebtAmount / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember |  |  | 150,000,000 us-gaap_ExtinguishmentOfDebtAmount / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember |
Redemption price per $1,000 principal notes | 960 noa_DebtInstrumentRedemptionPriceAmount / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember |  |  |  |  |
Redemption price, threshold amount | 1,000 noa_DebtInstrumentRedemptionPriceThresholdAmount / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember |  |  |  |  |
Accrued and unpaid interest |  |  |  | 100,000 noa_PaymentsofDebtExtinguishmentCostsAccruedandUnpaidInterest / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember | 5,300,000 noa_PaymentsofDebtExtinguishmentCostsAccruedandUnpaidInterest / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember |
Gain (loss) on debt extinguishment |  | 300,000 us-gaap_GainsLossesOnExtinguishmentOfDebt / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember |  | (300,000)us-gaap_GainsLossesOnExtinguishmentOfDebt / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember | (6,500,000)us-gaap_GainsLossesOnExtinguishmentOfDebt / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember |
Corporate debentures | Series 1 Debentures | On or after April 7, 2014 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Redemption price as a percentage of the principal amount |  |  |  | 103.042%us-gaap_DebtInstrumentRedemptionPricePercentage / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_DebtInstrumentRedemptionPeriodAxis = us-gaap_DebtInstrumentRedemptionPeriodOneMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember |  |
Corporate debentures | Series 1 Debentures | On or after April 7, 2015 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Redemption price as a percentage of the principal amount |  |  |  | 101.52%us-gaap_DebtInstrumentRedemptionPricePercentage / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_DebtInstrumentRedemptionPeriodAxis = us-gaap_DebtInstrumentRedemptionPeriodTwoMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember |  |
Corporate debentures | Series 1 Debentures | On or after April 7, 2016 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Redemption price as a percentage of the principal amount |  |  |  | 100.00%us-gaap_DebtInstrumentRedemptionPricePercentage / us-gaap_DebtInstrumentAxis = noa_Series1DebenturesMember / us-gaap_DebtInstrumentRedemptionPeriodAxis = us-gaap_DebtInstrumentRedemptionPeriodThreeMember / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember |  |

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- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400 + Details
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- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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