v3.8.0.1
Document and Entity Information - shares
9 Months Ended
Sep. 30, 2017
Oct. 24, 2017
Document And Entity Information    
Entity Registrant Name ACME UNITED CORP  
Entity Central Index Key 0000002098  
Document Type 10-Q  
Document Period End Date Sep. 30, 2017  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
Is Entity a Well-known Seasoned Issuer? No  
Is Entity a Voluntary Filer? No  
Is Entity's Reporting Status Current? Yes  
Entity Filer Category Smaller Reporting Company  
Entity Common Stock, Shares Outstanding   3,374,061
Document Fiscal Period Focus Q3  
Document Fiscal Year Focus 2017