v3.7.0.1
Document And Entity Information - shares
6 Months Ended
Feb. 28, 2017
Apr. 11, 2017
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 Smaller Reporting Company  
Entity Current Reporting Status Yes  
Entity Voluntary Filers No  
Entity Well-known Seasoned Issuer No  
Entity Common Stock, Shares Outstanding (in shares)   4,524,970
Document Type 10-Q  
Document Period End Date Feb. 28, 2017  
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q2  
Amendment Flag false