XML 40 R71.htm IDEA: XBRL DOCUMENT v2.4.1.9
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           225,000,000us-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     10,000,000noa_ExtinguishmentofDebtAmountElectedtobeRedeemed
/ us-gaap_DebtInstrumentAxis
= noa_Series1DebenturesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CorporateDebtSecuritiesMember
     
Redemption amount of Series 1 Debentures 6,300,000us-gaap_ExtinguishmentOfDebtAmount
/ us-gaap_DebtInstrumentAxis
= noa_Series1DebenturesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CorporateDebtSecuritiesMember
10,000,000us-gaap_ExtinguishmentOfDebtAmount
/ us-gaap_DebtInstrumentAxis
= noa_Series1DebenturesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CorporateDebtSecuritiesMember
    150,000,000us-gaap_ExtinguishmentOfDebtAmount
/ us-gaap_DebtInstrumentAxis
= noa_Series1DebenturesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CorporateDebtSecuritiesMember
 
Redemption price per $1,000 principal notes 960noa_DebtInstrumentRedemptionPriceAmount
/ us-gaap_DebtInstrumentAxis
= noa_Series1DebenturesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CorporateDebtSecuritiesMember
         
Redemption price, threshold amount 1,000noa_DebtInstrumentRedemptionPriceThresholdAmount
/ us-gaap_DebtInstrumentAxis
= noa_Series1DebenturesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CorporateDebtSecuritiesMember
         
Accrued and unpaid interest       100,000noa_PaymentsofDebtExtinguishmentCostsAccruedandUnpaidInterest
/ us-gaap_DebtInstrumentAxis
= noa_Series1DebenturesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CorporateDebtSecuritiesMember
5,300,000noa_PaymentsofDebtExtinguishmentCostsAccruedandUnpaidInterest
/ us-gaap_DebtInstrumentAxis
= noa_Series1DebenturesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CorporateDebtSecuritiesMember
 
Gain (loss) on debt extinguishment   300,000us-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