Note 8 - Employee Benefit Plans (Detail) (USD $)	3 Months Ended						9 Months Ended		24 Months Ended	141 Months Ended	144 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Jul. 02, 2011	Apr. 02, 2011	Jan. 01, 2011	Jun. 30, 2012	Jul. 02, 2011	Oct. 01, 2011	Jun. 30, 2012	Jun. 30, 2012
Defined Benefit Plans, General Information										Under the SERPs, if the Participant remains in continuous service with the Company for a period of at least 30years, the Company will pay to the Participant a supplemental retirement benefit for the 15-year period following the Participant's retirement equal to 50% of the Participant's highest average annual base salary for five consecutive years in the 10-year period preceding the Participant's retirement. If the Participant retires prior to the later of age 65 or the completion of 30years of continuous service with the Company, but has completed at least 10 years of continuous service with the Company, the amount of the supplemental retirement benefit will be reduced by 1/360th for each month short of 30years that the Participant was employed by the Company	Retirement plans. The Company has one defined benefit pension plan, the Insteel Wire Products Company Retirement Income Plan for Hourly Employees, Wilmington, Delaware (the "Delaware Plan"). The Delaware Plan provides benefits for eligible employees based primarily upon years of service and compensation levels. The Delaware Plan was frozen effective September 30, 2008 whereby participants will no longer earn additional service benefits. The Company's funding policy is to contribute amounts at least equal to those required by law. The Company made contributions totaling $88,000 and $164,000 to the Delaware Plan during the three- and nine-month periods ended June 30, 2012, respectively, and expects to contribute an additional $42,000 during the remainder of the current fiscal year. In February 2011, as part of the planned closure of the Wilmington, Delaware facility, the Company amended the Delaware Plan granting certain participants additional service credit. The amendment resulted in a one-time charge of $306,000 that was recorded in restructuring charges in fiscal 2011
Pension Contributions	$ 88,000						$ 164,000
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	42,000						42,000			42,000	42,000
Restructuring Charges	$ 30,000	$ 203,000	$ 599,000	$ 1,970,000	$ 2,213,000	$ 4,390,000	$ 832,000	$ 8,573,000	$ 306,000