Document And Entity Information
9 Months Ended
May 31, 2012
Jul. 13, 2012
Document and Entity Information [Abstract]    
Entity Registrant Name Northern Technologies International Corporation  
Document Type 10-Q  
Current Fiscal Year End Date --08-31  
Entity Common Stock, Shares Outstanding   4,401,656
Amendment Flag false  
Entity Central Index Key 0000875582  
Entity Current Reporting Status Yes  
Entity Voluntary Filers No  
Entity Filer Category Smaller Reporting Company  
Entity Well-known Seasoned Issuer No  
Document Period End Date May 31, 2012  
Document Fiscal Year Focus 2012  
Document Fiscal Period Focus Q3