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v2.4.1.9

Consolidated Balance Sheets (Parenthetical) | 12 Months Ended
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Dec. 31, 2014 | Dec. 31, 2013
Statement of Financial Position [Abstract] |  |
Common shares, authorized | unlimited | unlimited

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- Definition Common stock share authorized. + References No definition available. + Details
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Namespace Prefix: | noa_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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