Loss Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Numerator
Numerator for basic income (loss) per common share - loss from continuing operations	$ (3,197)	$ (11,901)	$ 7,796	$ (39,244)
Net income attributable to the noncontrolling interests	(1,685)	(1,911)	(4,796)	(4,407)
Net income (loss) attributable to MDC Partners Inc. common shareholders	(4,882)	(13,812)	3,000	(43,651)
Effect of dilutive securities	0	0	0	0
Numerator for diluted income (loss) per common share - loss attributable to MDC Partners Inc. common shareholders from continuing operations	$ (4,882)	$ (13,812)	$ 3,000	$ (43,651)
Denominator
Denominator for basic income (loss) per common share - weighted average common shares	49,630,532	47,205,699	49,506,427	47,052,944
Effect of dilutive securities	0	0	627,836	0
Denominator for diluted income (loss) per common share - adjusted weighted shares and assumed conversions	49,630,532	47,205,699	50,134,263	47,052,944
Income (loss) from continuing operations attributable to MDC Partners Inc. common shareholders (usd per share)	$ (0.10)	$ (0.29)	$ 0.06	$ (0.93)
Income (loss) from continuing operations attributable to MDC Partners Inc. common shareholders (usd per share)	$ (0.10)	$ (0.29)	$ 0.06	$ (0.93)