XML 12 R1.htm IDEA: XBRL DOCUMENT v3.10.0.1
Document and Entity Information - shares
 9 Months Ended
Sep. 30, 2018
Oct. 31, 2018
Document and Entity Information [Abstract]    
Entity Registrant Name Cohen & Co Inc.  
Entity Central Index Key 0001270436  
Document Type 10-Q  
Document Period End Date Sep. 30, 2018  
Amendment Flag false  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q3  
Current Fiscal Year End Date --12-31  
Trading Symbol cohn  
Entity Emerging Growth Company false  
Entity Small Business true  
Entity Filer Category Non-accelerated Filer  
Entity Common Stock, Shares Outstanding   1,215,512