Cover	12 Months Ended
Cover	Sep. 27, 2025
Cover [Abstract]
Document Type	DEF 14A
Entity Registrant Name	Insteel Industries Inc.
Entity Central Index Key	0000764401
Amendment Flag	false

Pay vs Performance Disclosure

12 Months Ended

24 Months Ended

36 Months Ended

48 Months Ended

60 Months Ended

Sep. 27, 2025

USD ($)

Sep. 28, 2024

USD ($)

Sep. 30, 2023

USD ($)

Oct. 01, 2022

USD ($)

Oct. 02, 2021

USD ($)

Oct. 01, 2022

USD ($)

Sep. 30, 2023

USD ($)

Sep. 28, 2024

USD ($)

Sep. 27, 2025

USD ($)

Pay vs Performance Disclosure [Table]

Pay vs Performance Disclosure, Table

Pay Versus Performance

Pursuant to Item 402(v) of SEC Regulation S-K, we are providing the following disclosure regarding executive compensation for our principal executive officer (“PEO”), Mr. Woltz, and our other NEOs (“Non-PEO NEOs”) and Company performance for the fiscal years listed below.


Year	Summary Compensation Table Total for H.O. Woltz III ($)	Compensation Actually Paid to H.O. Woltz III⁽¹⁾⁽²⁾ ($)	Average Summary Compensation Table Total for Non-PEO NEOs⁽³⁾ ($)	Average Compensation Actually Paid to Non-PEO NEOs^(1)(2)(3) ($)	Value of Initial Fixed $100 Investment Based on:		Net income ($ Thousands)	Return on Invested Capital⁽⁵⁾ (%)
Year					Total Shareholder Return ($)	Peer Group Total Shareholder Return⁽⁴⁾ ($)	Net income ($ Thousands)	Return on Invested Capital⁽⁵⁾ (%)
2025	3,447,259	3,798,936	981,681	1,069,473	274.64	231.94	41,020	14.1
2024	2,104,016	1,717,527	697,553	587,848	212.31	231.87	19,305	6.3
2023	2,146,512	2,297,925	594,499	553,469	207.28	146.15	32,415	9.1
2022	2,503,834	1,508,180	924,155	672,291	157.60	109.34	125,011	47.6
2021	2,475,749	4,043,446	972,237	1,368,777	219.98	144.86	66,610	36.9

Named Executive Officers, Footnote

(1)

The amounts shown for Compensation Actually Paid have been calculated in accordance with Item 402(v) of Regulation S-K, and therefore use hypothetical values and points in time when pay may not actually have been earned or delivered to the NEOs. These amounts reflect total compensation as reported in the Summary Compensation Table with certain adjustments as described in footnote 2 below.

Peer Group Issuers, Footnote [Text Block]

(4)

The Peer Group Total Shareholder Return shown in this table utilizes the S&P 500 Building Products Index, which we also utilize in the stock performance graph required by Item 201(e) of Regulation S-K, for the years reflected in the table above. The comparison assumes $100 was invested for the period starting October 3, 2020, through the end of the listed year in each of the Company and the S&P Building 500 Products Index. The historical stock price performance of our common stock shown is not necessarily indicative of future stock price performance.

PEO Total Compensation Amount

$ 3,447,259

$ 2,104,016

$ 2,146,512

$ 2,503,834

$ 2,475,749

PEO Actually Paid Compensation Amount

$ 3,798,936

1,717,527

2,297,925

1,508,180

4,043,446

Adjustment To PEO Compensation, Footnote

H.O. Woltz III

Year	Summary Compensation Table Total ($)	Exclusion of Change in Pension Value ($)	Exclusion of Stock Awards and Option Awards ($)	Inclusion of Pension Service Cost ($)	Inclusion of Equity Values ($)		Compensation Actually Paid ($)
2025	3,447,259	6,564	1,124,995	—	1,483,236		3,798,936
2024	2,104,016	177,548	912,516	—	703,575		1,717,527
2023	2,146,512	—	700,001	—	851,414		2,297,925
2022	2,503,834	—	650,001	—	(345,653	)	1,508,180
2021	2,475,749	195,092	600,027	46,686	2,316,130		4,043,446

H.O. Woltz III

Year	Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year ($)	Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards ($)		Vesting Date Fair Value of Equity Awards Granted During Year that Vested During Year ($)	Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year ($)		Fair Value at Last Day of Prior Year of Equity Awards Forfeited During Year ($)	Value of Dividends or Other Earnings Paid on Equity Awards Not Otherwise Included ($)	Total - Inclusion of Equity Values ($)
2025	1,226,727	241,421		—	15,088		—	—	1,483,236
2024	796,871	(81,398	)	—	(11,898	)	—	—	703,575
2023	671,800	109,575		—	70,039		—	—	851,414
2022	436,799	(561,775	)	—	(220,677	)	—	—	(345,653)
2021	683,259	1,129,842		—	503,029		—	—	2,316,130

Non-PEO NEO Average Total Compensation Amount

$ 981,681

697,553

594,499

924,155

972,237

Non-PEO NEO Average Compensation Actually Paid Amount

$ 1,069,473

587,848

553,469

672,291

1,368,777

Adjustment to Non-PEO NEO Compensation Footnote [Text Block]

Non-PEO NEOs (Average)

Year	Summary Compensation Table Total ($)	Exclusion of Change in Pension Value ($)	Exclusion of Stock Awards and Option Awards ($)	Inclusion of Pension Service Cost ($)	Inclusion of Equity Values ($)		Compensation Actually Paid ($)
2025	981,681	35,168	206,252	41,200	288,012		1,069,473
2024	697,553	96,938	206,247	41,515	151,965		587,848
2023	594,499	19,971	150,000	30,438	98,503		553,469
2022	924,155	8,192	206,242	48,049	(85,479	)	672,291
2021	972,237	80,988	196,254	47,191	626,592		1,368,777

Non-PEO NEOs (Average)

Year	Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year ($)	Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards ($)		Vesting Date Fair Value of Equity Awards Granted During Year that Vested During Year ($)	Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year ($)		Fair Value at Last Day of Prior Year of Equity Awards Forfeited During Year ($)		Value of Dividends or Other Earnings Paid on Equity Awards Not Otherwise Included ($)	Total - Inclusion of Equity Values ($)
2025	224,903	60,901		—	2,208		—		—	288,012
2024	177,685	(21,465	)	—	(4,255	)	—		—	151,965
2023	143,885	23,577		—	15,115		(84,074	)	—	98,503
2022	137,475	(166,711	)	—	(56,242	)	—		—	(85,479)
2021	223,475	284,514		—	118,603		—		—	626,592

Compensation Actually Paid vs. Total Shareholder Return [Text Block]

DESCRIPTION OF RELATIONSHIP BETWEEN PEO AND OTHER NEO COMPENSATION ACTUALLY PAID AND INSTEEL TOTAL SHAREHOLDER RETURN (“TSR”)

The following chart sets forth the relationship between Compensation Actually Paid to Mr. Woltz, the average of Compensation Actually Paid to our other NEOs, and our cumulative TSR over the three most recently completed fiscal years.

Compensation Actually Paid vs. Net Income [Text Block]

DESCRIPTION OF RELATIONSHIP BETWEEN PEO AND OTHER NEO COMPENSATION ACTUALLY PAID AND NET INCOME

The following chart sets forth the relationship between Compensation Actually Paid to Mr. Woltz, the average of Compensation Actually Paid to our other NEOs, and our net income over the three most recently completed fiscal years.

Compensation Actually Paid vs. Company Selected Measure [Text Block]

DESCRIPTION OF RELATIONSHIP BETWEEN PEO AND OTHER NEO COMPENSATION ACTUALLY PAID AND RETURN ON INVESTED CAPITAL

The following chart sets forth the relationship between Compensation Actually Paid to Mr. Woltz, the average of Compensation Actually Paid to our other NEOs, and our return on invested capital over the three most recently completed fiscal years.

Total Shareholder Return Vs Peer Group [Text Block]

DESCRIPTION OF RELATIONSHIP BETWEEN INSTEEL TSR AND PEER GROUP TSR

The following chart compares our cumulative TSR over the three most recently completed fiscal years to that of the S&P 500 Building Products Index over the same period.

Tabular List [Table Text Block]

MOST IMPORTANT FINANCIAL MEASURE

The Committee believes that return on invested capital was, for the most recently completed fiscal year, the most appropriate metric for linking pay and performance in that it is driven off both the generation of earnings and responsible management of our balance sheet and is closely correlated with the creation of shareholder value. Return on invested capital was the only financial measure used by Insteel to link the Compensation Actually Paid to Mr. Woltz and our other NEOs for fiscal 2025 to company performance. The Committee does not utilize nonfinancial performance metrics to determine the compensation of Mr. Woltz or our other NEOs.

Total Shareholder Return Amount

219.98

$ 157.60

$ 207.28

$ 212.31

$ 274.64

Peer Group Total Shareholder Return Amount

144.86

$ 109.34

$ 146.15

$ 231.87

$ 231.94

Net Income (Loss) Attributable to Parent

$ 41,020,000

$ 19,305,000

$ 32,415,000

$ 125,011,000

$ 66,610,000

Company Selected Measure Amount

14.1

6.3

9.1

47.6

36.9

PEO Name

H.O. Woltz III

Measure [Axis]: 1

Pay vs Performance Disclosure [Table]

Name

return on invested capital

Non-GAAP Measure Description [Text Block]

(5)

We determined return on capital to be the most important financial performance measure used to link our performance to Compensation Actually Paid to Mr. Woltz and our non-PEO NEOs in fiscal 2025. For purposes of this disclosure, return on capital was calculated by dividing the Company’s Net Operating Profit After Tax for each fiscal period by its total Invested Capital for such fiscal period, each as defined in the Company’s Return on Capital Incentive Compensation Plan.

PEO [Member] | Exclusion Of Change In Pension Value [Member]

Award Timing Disclosure	12 Months Ended
Award Timing Disclosure	Sep. 27, 2025
Awards Close in Time to MNPI Disclosures [Table]
Award Timing MNPI Disclosure	The Executive Compensation Committee generally approves the grant of RSUs and stock options to our directors, executive officers and eligible employees on a predetermined schedule at its meeting each February. The RSUs and stock options are awarded in two equal tranches, with the first tranche granted on the date of our annual meeting of shareholders each February and the second tranche granted on the date that is six months after the date of such meeting. These dates are typically about three weeks after the announcement of our quarterly financial results. The Executive Compensation Committee does not take material nonpublic information into account when determining the timing and terms of equity awards. The Company has not timed the disclosure of material nonpublic information to affect the value of executive compensation. Any coordination between a grant and the release of information that could be expected to affect such grant’s value is precluded by the predetermined schedule.
Award Timing Method	The Executive Compensation Committee generally approves the grant of RSUs and stock options to our directors, executive officers and eligible employees on a predetermined schedule at its meeting each February. The RSUs and stock options are awarded in two equal tranches, with the first tranche granted on the date of our annual meeting of shareholders each February and the second tranche granted on the date that is six months after the date of such meeting. These dates are typically about three weeks after the announcement of our quarterly financial results.
Award Timing Predetermined	true
Award Timing MNPI Considered	false
Award Timing, How MNPI Considered	The Executive Compensation Committee does not take material nonpublic information into account when determining the timing and terms of equity awards. The Company has not timed the disclosure of material nonpublic information to affect the value of executive compensation.
MNPI Disclosure Timed for Compensation Value	false

Insider Trading Policies and Procedures	12 Months Ended
Insider Trading Policies and Procedures	Sep. 27, 2025
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true