Note F -Defined Benefit Pension Plan (Details Textual)	6 Months Ended
Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Number of Years Compensation Used for Benefit Obligation Assumptions	5 years

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.

No definition available.

Name:	naii_NumberOfYearsCompensationUsedForBenefitObligationAssumptions
Namespace Prefix:	naii_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration