The fixed charge coverage ratio under debt instrument covenant.

No definition available.

Name:	naii_DebtInstrumentCovenantFixedChargeCoverageRatio
Namespace Prefix:	naii_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

The maximum net loss allowed related to a covenant for debt instruments.

+ References

No definition available.

+ Details

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Namespace Prefix:	naii_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The net income required under debt instrument covenant minimum.

+ References

No definition available.

+ Details

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Namespace Prefix:	naii_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of the fee that accompanies the extension of the loan agreement and related promissory note maturity date.

+ References

No definition available.

+ Details

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Namespace Prefix:	naii_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

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-Name Accounting Standards Codification
-Section S99
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-Subparagraph (SX 210.5-02(22)(b))
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The effective interest rate during the reporting period.

+ References

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Balance Type:	credit
Period Type:	instant

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Balance Type:
Period Type:

- Details

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- Details

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- Details

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Note F - Debt (Details Textual)			3 Months Ended		6 Months Ended
Note F - Debt (Details Textual)	Jun. 30, 2025 USD ($)	Aug. 18, 2021 USD ($)	Mar. 31, 2026 USD ($)	Sep. 30, 2025 USD ($)	Dec. 31, 2025 USD ($)	Jun. 20, 2025 USD ($)	Feb. 13, 2024 USD ($)
Line of Credit, Current	$ 1,900,000			$ 2,451,000
Wells Fargo Bank, N.A. [Member] \| Credit Agreement [Member]
Line of Credit Facility, Maximum Borrowing Capacity						$ 10,000,000	$ 12,500,000
Line of Credit Facility, Interest Rate During Period	3.25%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.375%
Debt Instrument, Covenant, Maximum Net Loss Allowed				$ 250,000	$ 750,000
Debt Instrument Covenant, Fixed Charge Coverage Ratio				1
Notes, Loans and Financing Receivable, Extension Fee	$ 20,000
Line of Credit Facility, Current Borrowing Capacity				$ 10,000,000
Line of Credit, Current				2,500,000
Wells Fargo Bank, N.A. [Member] \| Credit Agreement [Member] \| Term Loan [Member]
Debt Instrument, Face Amount		$ 10,000,000
Debt Instrument, Term (Year)		7 years
Debt Instrument, Basis Spread on Variable Rate		1.80%
Long-Term Debt				$ 8,900,000
Wells Fargo Bank, N.A. [Member] \| Credit Agreement [Member] \| Forecast [Member]
Debt Instrument Covenant Minimum, Net Income Required			$ 1
Debt Instrument Covenant, Fixed Charge Coverage Ratio					1.25