v3.5.0.2
Document And Entity Information - shares
9 Months Ended
May 31, 2016
Jul. 08, 2016
Document Information [Line Items]    
Entity Registrant Name Northern Technologies International Corporation  
Entity Central Index Key 0000875582  
Trading Symbol ntic  
Current Fiscal Year End Date --08-31  
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)   4,537,116
Document Type 10-Q  
Document Period End Date May 31, 2016  
Document Fiscal Year Focus 2016  
Document Fiscal Period Focus Q3  
Amendment Flag false