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Significant Accounting Policies - Property, Plant and Equipment (Details)	12 Months Ended
	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

X

- Details

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

X

- 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