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Shares - Common stock issued and outstanding (Details) (CAD) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, issued (shares)	34,746,236us-gaap_CommonStockSharesIssued		36,251,006us-gaap_CommonStockSharesIssued
Beginning balance, outstanding (shares)	34,746,236us-gaap_CommonStockSharesOutstanding		36,251,006us-gaap_CommonStockSharesOutstanding
Issued upon exercise of stock options (shares)			295,230us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
Purchase of treasury shares for settlement of certain equity classified stock-based compensation	(589,892)us-gaap_TreasuryStockSharesAcquired
Retired through Share Purchase Program (shares)	(500,000)noa_StockRepurchaseProgramNumberofSharestobePurchasedandRetired		(1,800,000)noa_StockRepurchaseProgramNumberofSharestobePurchasedandRetired
Ending balance, issued (shares)	34,923,916us-gaap_CommonStockSharesIssued		34,746,236us-gaap_CommonStockSharesIssued
Ending balance, outstanding (shares)	34,334,024us-gaap_CommonStockSharesOutstanding		34,746,236us-gaap_CommonStockSharesOutstanding
Earnings Per Share [Abstract]
Net loss from continuing operations	(697)us-gaap_IncomeLossFromContinuingOperations		(18,047)us-gaap_IncomeLossFromContinuingOperations
Net (loss) income from discontinued operations	(472)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity		87,231us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity
Net (loss) income	(1,169)us-gaap_NetIncomeLoss		69,184us-gaap_NetIncomeLoss
Weighted average number of shares outstanding, basic
Weighted average number of common shares (in shares)	35,014,418us-gaap_WeightedAverageNumberOfSharesOutstandingBasic		36,269,996us-gaap_WeightedAverageNumberOfSharesOutstandingBasic
Basic per share information
Net loss from continuing operations (in CAD per share)	(0.02)us-gaap_IncomeLossFromContinuingOperationsPerBasicShare		(0.50)us-gaap_IncomeLossFromContinuingOperationsPerBasicShare
Net (loss) income from discontinued operations	(0.01)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare		2.41us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare
Net income (loss) (in CAD per share)	(0.03)us-gaap_EarningsPerShareBasic		1.91us-gaap_EarningsPerShareBasic
Dilutive effect of stock options (in shares)	0us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements		342,957us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements
Weighted average number of shares outstanding, diluted
Weighted average number of diluted common shares (in shares)	35,014,418us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding		36,612,953us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding
Diluted per share information
Net loss from continuing operations (in CAD per share)	(0.02)us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare		(0.50)us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare
Net (loss) income from discontinued operations	(0.01)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare		2.39us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare
Net income (loss) (in CAD per share)	(0.03)us-gaap_EarningsPerShareDiluted		1.89us-gaap_EarningsPerShareDiluted
Share option plan
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issued upon exercise of stock options (shares)	385,880us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised / us-gaap_PlanNameAxis = noa_ShareOptionPlanMember	[1]	295,230us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised / us-gaap_PlanNameAxis = noa_ShareOptionPlanMember	[1]
Senior executive stock option plan
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issued upon exercise of stock options (shares)	291,800us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised / us-gaap_PlanNameAxis = noa_SeniorExecutiveStockOptionPlanMember		0us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised / us-gaap_PlanNameAxis = noa_SeniorExecutiveStockOptionPlanMember
Treasury shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, outstanding (shares)	0us-gaap_CommonStockSharesOutstanding / us-gaap_StatementEquityComponentsAxis = us-gaap_TreasuryStockMember
Purchase of treasury shares for settlement of certain equity classified stock-based compensation	(589,892)us-gaap_TreasuryStockSharesAcquired / us-gaap_StatementEquityComponentsAxis = us-gaap_TreasuryStockMember
Ending balance, outstanding (shares)	(589,892)us-gaap_CommonStockSharesOutstanding / us-gaap_StatementEquityComponentsAxis = us-gaap_TreasuryStockMember
[1] All stock options exercised resulted in new common shares being issued (note 17(a))

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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