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Contingencies | 12 Months Ended
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Dec. 31, 2015
Contingencies Disclosure [Abstract] |
Contingencies | Contingencies During the normal course of the Company’s operations, various legal and tax matters are pending. In the opinion of management, these matters will not have a material effect on the Company’s consolidated financial position or results of operations.

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- Definition Contingencies Disclosure [Abstract] + 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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- Definition The entire disclosure for legal proceedings, legal contingencies, litigation, regulatory and environmental matters and other contingencies. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration