CONDENSED STATEMENTS OF SHAREHOLDERS' DEFICIT - USD ($) $ in Thousands	Total	Common Class A	Convertible Preferred Stock [Member] Series 4 Convertible Preferred Stock [Domain]	Common Stock	Common Stock Common Class A	Common Stock Common Class B	Share Capital To Be Issued [Member]	Share Capital To Be Issued [Member] Common Class A	Additional Paid-in Capital	Charges in Excess of Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Parent [Member]	Noncontrolling Interest [Member]
Common Stock, Value, Issued		$ 317,784
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares, To be Issued							100,000
Common Stock, Value, To be Issued							$ 2,360	$ 2,360
Balance at Dec. 31, 2016	$ (509,476)		$ 0	$ 317,784					$ 0	$ (311,581)	$ (581,848)	$ (1,824)	$ (575,109)	$ 65,633
Balance (in shares) at Dec. 31, 2016			0	52,802,058	52,798,303	3,755
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss attributable to MDC Partners Inc.	687										687		687	0
Other Comprehensive income (loss)	618											(653)	(653)	1,271
Issuance of restricted stock	$ 0			$ 3,593					(3,593)				$ 0
Stock Issued During Period, Shares, New Issues	90,220,000		95,000										90,220,000
Stock Issued During Period, Value, Convertible Preferred Shares			$ 90,220
Deferred acquisition consideration settled through issuance of shares	$ 27,852			$ 28,727					1,485				$ 27,852
Stock Authorized During Period, Shares, To be Issued							(100,000)
Stock Authorized During Period, Value, To be Issued							$ (2,360)
Issuance of restricted stock (in shares)				173,550
Shares acquired and cancelled	(630)			$ (630)									(630)
Stock Issued During Period, Shares, New Issues				3,353,939
Shares acquired and cancelled (in shares)				(69,225)
Stock-based compensation	3,769								3,769				3,769
Temporary Equity, Accretion to Redemption Value	(2,783)								(2,783)				(2,783)
Noncontrolling Interest, Increase from Business Combination	(9,295)								2,652				2,652
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	11,947													(11,947)
Transfer to charges in excess of capital									(1,530)	1,530
Balance at Jun. 30, 2017	(399,038)		$ 90,220						0	(310,051)	(581,161)	(2,477)	(453,995)	54,957
Balance (in shares) at Jun. 30, 2017			95,000	56,260,322	56,256,567
Balance (in shares) at Mar. 31, 2017						3,755
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss attributable to MDC Partners Inc.	11,253
Other Comprehensive income (loss)	550
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	11,947
Balance at Jun. 30, 2017	$ (399,038)		$ 90,220						$ 0	$ (310,051)	$ (581,161)	$ (2,477)	$ (453,995)	$ 54,957
Balance (in shares) at Jun. 30, 2017			95,000	56,260,322	56,256,567
Common Stock, Value, Issued		$ 349,474		$ 349,474
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares, To be Issued							0
Common Stock, Value, To be Issued							$ 0	$ 0