v3.19.1
Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2018
Mar. 08, 2019
Jun. 30, 2018
Document And Entity Information      
Entity Registrant Name ACME UNITED CORP    
Entity Central Index Key 0000002098    
Document Type 10-K    
Document Period End Date Dec. 31, 2018    
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 Accelerated Filer    
Entity Common Stock, Shares Outstanding   3,350,833  
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2018    
Entity Public Float     $ 61,417,386
Entity Emerging Growth Company? false    
Entity Small Business? true    
Entity Shell Company? false