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Significant Accounting Policies - Property, Plant and Equipment (Details) | 12 Months Ended
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Mar. 31, 2013
Other equipment | Minimum |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment, useful life | 5 years
Other equipment | Maximum |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment, useful life | 10 years
Licensed motor vehicles |
Property, Plant and Equipment [Line Items] |
Declining balance depreciation rate | 30.00%
Office and computer equipment |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment, useful life | 4 years
Buildings |
Property, Plant and Equipment [Line Items] |
Property, plant and equipment, useful life | 10 years

X
- Definition Property, Plant and Equipment, Annual Declining Balance Depreciation Rate + References No definition available. + Details
Name: | noa_PropertyPlantAndEquipmentAnnualDecliningBalanceDepreciationRate
Namespace Prefix: | noa_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- Details
Name: | us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration