Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 27, 2017	Dec. 31, 2016
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
Document Type	10-Q
Document Fiscal Year Focus	2017
Document Period End Date	Sep. 30, 2017
Document Fiscal Period Focus	Q3
Amendment Flag	false
Common Class A
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		58,357,062
Common Class B
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		3,755
Convertible Preferred Stock [Member] | Series 4 Convertible Preferred Stock [Domain]
Document Information [Line Items]
Stock Issued During Period, Shares, Convertible Preferred Shares	95,000	95,000	0