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Employee benefit plans (Details) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2018 CAD ($) $ / h | Dec. 31, 2017 CAD ($)
Retirement Benefits [Abstract] |  |
Contributions made by the Company during the year | $ | $ 991 | $ 877
Company match of voluntary contributions made by employees, percentage of base salary | 5.00% |
Contribution per hour | $ / h | 1.00 |

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- Definition Defined Contribution Plan, Employer Matching Contribution, Contribution Per Hour + References No definition available. + Details
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Namespace Prefix: | noa_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | duration

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- References No definition available. + Details
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Namespace Prefix: | us-gaap_
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Balance Type: | na
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- Definition Amount of cost for defined contribution plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
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Namespace Prefix: | us-gaap_
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Balance Type: | debit
Period Type: | duration

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- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
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Balance Type: | na
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