Noncontrolling and Redeemable Noncontrolling Interests - Changes in Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Noncontrolling Interest [Line Items]
Net loss attributable to MDC Partners Inc.	$ (593)	$ 4,290	$ 410	$ 4,177
Decrease in MDC Partners Inc. paid-in capital for purchase of redeemable noncontrolling interests and noncontrolling interests			(503)
Change from net income (loss) attributable to MDC Partners Inc. and transfers to noncontrolling interests	593	(4,193)	93	(4,080)
MDC Partners Inc. Shareholders' Deficit
Noncontrolling Interest [Line Items]
Net loss attributable to MDC Partners Inc.	(593)	4,290	410	4,177
Decrease in MDC Partners Inc. paid-in capital for purchase of redeemable noncontrolling interests and noncontrolling interests	$ 0	$ (97)	$ 503	$ 97

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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