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Note F - Employee Benefit Plans (Details) | 15 Months Ended
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Sep. 30, 2014
Compensation and Retirement Disclosure [Abstract] |
Number Of Years Compensation Used For Benefit Obligation Assumptions | 5 years

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- Definition Number Of Years Compensation Used For Benefit Obligation Assumptions + References No definition available. + Details
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Namespace Prefix: | naii_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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