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v2.4.1.9

Note F - Defined Benefit Pension Plan (Details Textual) | 9 Months Ended
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Mar. 31, 2015
Number of Years Compensation Used for Benefit Obligation Assumptions | 5 years

X
- Definition The period of employment before retirement that is used to determine what amount of compensation to use as a a baseline for the companies defined benefit plan. + References No definition available. + Details
Name: | naii_NumberOfYearsCompensationUsedForBenefitObligationAssumptions
Namespace Prefix: | naii_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration