v3.8.0.1
Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2017
Mar. 03, 2018
Jun. 30, 2017
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, 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 Accelerated Filer    
Entity Common Stock, Shares Outstanding   3,374,061  
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2017    
Entity Public Float     $ 84,519,435