v3.10.0.1
Document and Entity Information - shares
9 Months Ended
Sep. 30, 2018
Nov. 07, 2018
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, 2018  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
Is Entity's Reporting Status Current? Yes  
Is Entity an Emerging Growth Company? false  
Is Entity a Small Business? true  
Entity Filer Category Non-accelerated Filer  
Entity Common Stock, Shares Outstanding   3,369,061
Document Fiscal Period Focus Q3  
Document Fiscal Year Focus 2018