XML 12 R1.htm IDEA: XBRL DOCUMENT v3.3.1.900
Document And Entity Information - shares
 3 Months Ended
Jan. 02, 2016
Jan. 20, 2016
Entity Registrant Name INSTEEL INDUSTRIES INC  
Entity Central Index Key 0000764401  
Trading Symbol iiin  
Current Fiscal Year End Date --10-01  
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)   18,600,328
Document Type 10-Q  
Document Period End Date Jan. 02, 2016  
Document Fiscal Year Focus 2016  
Document Fiscal Period Focus Q1  
Amendment Flag false