Document And Entity Information	3 Months Ended
	Dec. 27, 2014	Jan. 14, 2014
Entity Registrant Name	INSTEEL INDUSTRIES INC
Entity Central Index Key	0000764401
Current Fiscal Year End Date	--10-03
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Common Stock, Shares Outstanding (in shares)		18,377,251
Document Type	10-Q
Document Period End Date	Dec. 27, 2014
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Amendment Flag	false