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Claims revenue (Details) (CAD) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Contractors [Abstract]
Claims revenue recognized	17,053	21,565
Claims revenue uncollected (classified as unbilled revenue)	8,074	21,942

X

- Definition

Revenues, Contract Claims

+ References

No definition available.

+ Details

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Namespace Prefix:	noa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

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Period Type:	duration

X

- Definition

Amount of billed or unbilled claims or other similar items subject to uncertainty concerning their determination or ultimate realization under long-term contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.3(c)(3))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph c(3)

-Article 5

+ Details

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