Loss per Common Share - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Net income attributable to MDC Partners	$ (81,598)	$ (16,125)	$ 3,406	$ (29,416)	$ 222,668	$ 18,493	$ 11,253	$ (10,566)	$ (123,733)	$ 241,848	$ (45,839)
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	$ (75,713)	$ (13,667)	$ 5,951	$ (28,519)	$ 231,455	$ 21,984	$ 13,467	$ (9,683)	(111,948)	257,223	(40,621)
Accretion on Convertible Preferred Shares									(8,355)	6,352	0
Net Income Allocated to Convertible Shares									0		0
Income (Loss) from Continuing Operations Attributable to Parent, Basic									(132,088)	205,594	(45,839)
Numerator:
Net income attributable to the noncontrolling interests									(11,785)	(15,375)	(5,218)
Income (Loss) from Continuing Operations Attributable to Parent											(45,839)
Adjustment to Net Income, Allocated to Convertible Shares									0	106	0
Income (Loss) from Continuing Operations Attributable to Parent, Diluted									$ (132,088)	$ 205,700	$ (45,839)
Denominator:
Basic weighted average number of common shares outstanding									57,218,994	55,255,797	51,345,807
Effect of dilutive securities:
Impact of stock options and non-vested stock under employee stock incentive plans									0	225,989	0
Diluted weighted average number of common shares outstanding									57,218,994	55,481,786	51,345,807
Income (Loss) from Continuing Operations, Per Basic Share									$ (2.31)	$ 3.72	$ (0.89)
Income (Loss) from Continuing Operations, Per Diluted Share									$ (2.31)	$ 3.71	$ (0.89)
Series 4 Convertible Preferred Stock [Member] | Convertible Preference Shares
Class of Stock [Line Items]
Accretion on Convertible Preferred Shares										$ (6,352)
Convertible preference shares | Convertible Preference Shares
Class of Stock [Line Items]
Accretion on Convertible Preferred Shares									$ (8,355)	(36,254)
Net Income Allocated to Convertible Shares										$ (29,902)