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Discontinued operations (Details) (CAD) | 12 Months Ended
--- | ---
Dec. 31, 2014 business | Dec. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |
Number of businesses disposed of in prior years | 2 noa_DisposalGroupIncludingDiscontinuedOperationNumberofBusinessesDisposed |
Costs related to discontinued operations during period | (472,000)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity | 87,231,000 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity
Results of discontinued operations |  |
Revenue |  | 98,735,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue
Project costs |  | 80,793,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold
Equipment costs |  | 1,242,000 noa_DisposalGroupIncludingDiscontinuedOperationEquipmentCosts
Depreciation |  | 706,000 noa_DisposalGroupIncludingDiscontinuedOperationDepreciation
Gross (loss) profit |  | 15,994,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss
General and administrative expenses |  | 7,169,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense
Loss (gain) on disposal of assets and liabilities |  | (98,002,000)us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax
Gain on sale of inventory |  | (46,000)noa_DisposalGroupIncludingDiscontinuedOperationGainLossOnSaleOfInventory
Amortization of intangible assets |  | 351,000 noa_DisposalGroupIncludingDiscontinuedOperationAmortizationOfIntangibleAssets
Operating (loss) income |  | 106,522,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss
Interest expense |  | 4,758,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense
(Loss) income before income taxes |  | 101,764,000 us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax
Current income tax expense |  | 164,000 noa_DiscontinuedOperationTaxEffectofIncomeLossfromDisposalofDiscontinuedOperationCurrent
Deferred income tax (benefit) expense |  | 14,369,000 noa_DiscontinuedOperationTaxEffectOfIncomeLossFromDisposalOfDiscontinuedOperationDeferred
Net (loss) income |  | 87,231,000 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax
Cash provided by (used in) the discontinued operations |  |
Operating activities | (472,000)us-gaap_CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations | 45,739,000 us-gaap_CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations
Investing activities | 0 us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations | 182,836,000 us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations
Financing activities | 0 us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations | (271,000)us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations
Total cash provided by (used in) discontinued operations | (472,000)us-gaap_NetCashProvidedByUsedInDiscontinuedOperations | 228,304,000 us-gaap_NetCashProvidedByUsedInDiscontinuedOperations
Pipeline |  |
Results of discontinued operations |  |
Revenue |  | 0 us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Project costs |  | 1,321,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Equipment costs |  | 0 noa_DisposalGroupIncludingDiscontinuedOperationEquipmentCosts / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Depreciation |  | 0 noa_DisposalGroupIncludingDiscontinuedOperationDepreciation / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Gross (loss) profit |  | (1,321,000)us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
General and administrative expenses |  | 312,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Loss (gain) on disposal of assets and liabilities |  | 63,000 us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Gain on sale of inventory |  | (46,000)noa_DisposalGroupIncludingDiscontinuedOperationGainLossOnSaleOfInventory / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Amortization of intangible assets |  | 0 noa_DisposalGroupIncludingDiscontinuedOperationAmortizationOfIntangibleAssets / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Operating (loss) income |  | (1,650,000)us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Interest expense |  | 0 us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
(Loss) income before income taxes |  | (1,650,000)us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Current income tax expense |  | 0 noa_DiscontinuedOperationTaxEffectofIncomeLossfromDisposalofDiscontinuedOperationCurrent / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Deferred income tax (benefit) expense |  | (510,000)noa_DiscontinuedOperationTaxEffectOfIncomeLossFromDisposalOfDiscontinuedOperationDeferred / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Net (loss) income |  | (1,140,000)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Cash provided by (used in) the discontinued operations |  |
Operating activities |  | (1,587,000)us-gaap_CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Investing activities |  | 0 us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Financing activities |  | 0 us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Total cash provided by (used in) discontinued operations |  | (1,587,000)us-gaap_NetCashProvidedByUsedInDiscontinuedOperations / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PipelineIntegrityAndMaintenanceIndustryMember
Piling |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |
Period to receive contingent consideration as part of sale | 3 years |
Results of discontinued operations |  |
Revenue |  | 98,735,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Project costs |  | 79,472,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Equipment costs |  | 1,242,000 noa_DisposalGroupIncludingDiscontinuedOperationEquipmentCosts / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Depreciation |  | 706,000 noa_DisposalGroupIncludingDiscontinuedOperationDepreciation / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Gross (loss) profit |  | 17,315,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
General and administrative expenses |  | 6,857,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Loss (gain) on disposal of assets and liabilities |  | (98,065,000)us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Gain on sale of inventory |  | 0 noa_DisposalGroupIncludingDiscontinuedOperationGainLossOnSaleOfInventory / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Amortization of intangible assets |  | 351,000 noa_DisposalGroupIncludingDiscontinuedOperationAmortizationOfIntangibleAssets / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Operating (loss) income |  | 108,172,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Interest expense |  | 4,758,000 us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
(Loss) income before income taxes |  | 103,414,000 us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Current income tax expense |  | 164,000 noa_DiscontinuedOperationTaxEffectofIncomeLossfromDisposalofDiscontinuedOperationCurrent / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Deferred income tax (benefit) expense |  | 14,879,000 noa_DiscontinuedOperationTaxEffectOfIncomeLossFromDisposalOfDiscontinuedOperationDeferred / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Net (loss) income |  | 88,371,000 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Cash provided by (used in) the discontinued operations |  |
Operating activities |  | 47,326,000 us-gaap_CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Investing activities |  | 182,836,000 us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Financing activities |  | (271,000)us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Total cash provided by (used in) discontinued operations |  | 229,891,000 us-gaap_NetCashProvidedByUsedInDiscontinuedOperations / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember
Maximum | Piling |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |
Contingent consideration, additional proceeds | 92,500 noa_DisposalGroupIncludingDiscontinuedOperationContingentConsiderationProceeds / us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis = noa_PilingMember / us-gaap_RangeAxis = us-gaap_MaximumMember |

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- Definition Increase (decrease) in cash associated with the entity's discontinued operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 24 -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3521-108585 + Details
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