Loss Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Earnings Per Share [Abstract]
Income from continuing operations	$ (5,166)	$ (1,868)	$ 2,489	$ 10,474
Numerator
Net income attributable to the noncontrolling interests	(2,122)	(1,685)	(7,343)	(4,796)	$ (6,890)
Income (Loss) from Continuing Operations Attributable to Parent	(7,288)	(3,553)	(4,854)	5,678
Effect of dilutive securities	0	0	0	0
Income (Loss) from Continuing Operations Attributable to Parent, Diluted	$ (7,288)	$ (3,553)	$ (4,854)	$ 5,678
Denominator
Denominator for basic income (loss) per common share - weighted average common shares	49,915,807	49,630,532	49,843,980	49,506,427
Effect of dilutive securities	0	0	0	627,836
Denominator for diluted income (loss) per common share - adjusted weighted shares and assumed conversions	49,915,807	49,630,532	49,843,980	50,134,263
Income (loss) from continuing operations attributable to MDC Partners Inc. common shareholders (usd per share)	$ (0.15)	$ (0.07)	$ (0.10)	$ 0.11
Income (loss) from continuing operations attributable to MDC Partners Inc. common shareholders (usd per share)	$ (0.15)	$ (0.07)	$ (0.10)	$ 0.11