XML 67 R45.htm IDEA: XBRL DOCUMENT v3.20.4

Significant accounting policies - Property, plant and equipment (Details)	12 Months Ended
	Dec. 31, 2020
Heavy equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3000 hours
Heavy equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	120000 hours
Major component parts in use | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3000 hours
Major component parts in use | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	50000 hours
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 | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Licensed motor vehicles | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Office and computer equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	4 years
Office and computer equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Furnishings, fixtures and facilities | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Furnishings, fixtures and facilities | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	30 years
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	50 years

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ 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

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=noa_HeavyEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=noa_MajorComponentPartsInUseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_OtherMachineryAndEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_VehiclesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=noa_OfficeAndComputerEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_FurnitureAndFixturesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: