XML 14 R1.htm IDEA: XBRL DOCUMENT v3.10.0.1
Document And Entity Information - shares
 9 Months Ended
Sep. 30, 2018
Oct. 31, 2018
Document Information [Line Items]    
Entity Registrant Name MDC PARTNERS INC  
Entity Central Index Key 0000876883  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Trading Symbol MDCA  
Entity Emerging Growth Company 0  
Document Type 10-Q  
Entity Small Business 0  
Document Fiscal Year Focus 2018  
Document Period End Date Sep. 30, 2018  
Document Fiscal Period Focus Q3  
Amendment Flag false  
Common Class A    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   59,809,581
Common Class B    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   3,755
Convertible Preferred Stock | Series 4 Convertible Preferred Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   95,000