CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Services	$ 1,199,011	$ 1,415,803	$ 1,475,088
Operating expenses:
Cost of services sold	769,899	961,076	991,198
Office and general expenses	341,565	328,339	349,056
Depreciation and amortization	36,905	38,329	46,196
Impairment and other losses	96,399	8,599	87,204
Costs and Expenses, Total	1,244,768	1,336,343	1,473,654
Operating income (loss)	(45,757)	79,460	1,434
Other income (expense):
Interest expense and finance charges, net	(62,163)	(64,942)	(67,075)
Foreign exchange gain (loss)	(982)	8,750	(23,258)
Other, net	20,500	(2,401)	230
Nonoperating Income (Expense), Total	(42,645)	(58,593)	(90,103)
Income (loss) before income taxes and equity in earnings of non-consolidated affiliates	(88,402)	20,867	(88,669)
Income tax expense	116,555	10,316	29,615
Income (loss) before equity in earnings of non-consolidated affiliates	(204,957)	10,551	(118,284)
Equity in earnings (losses) of non-consolidated affiliates	(2,240)	352	62
Net income (loss)	(207,197)	10,903	(118,222)
Net income attributable to the noncontrolling interest	(21,774)	(16,156)	(11,785)
Net loss attributable to MDC Partners Inc.	(228,971)	(5,253)	(130,007)
Net loss attributable to MDC Partners Inc. common shareholders	$ (243,150)	$ (17,557)	$ (138,362)
Basic and diluted
Earnings per share, basic	$ (3.34)	$ (0.25)	$ (2.42)
Earnings per share, diluted	$ (3.34)	$ (0.25)	$ (2.42)
Weighted Average Number of Common Shares Outstanding:
Weighted Average Number of Shares Outstanding, Basic	72,862,178	69,132,100	57,218,994
Weighted Average Number of Shares Outstanding, Diluted	72,862,178	69,132,100	57,218,994
Series 4 Convertible Preferred Stock | Convertible Preference Shares
Other income (expense):
Accretion on and net income allocated to convertible preference shares	$ (14,179)	$ (12,304)	$ (8,355)