Adjustments to Additional Paid in Capital, Changes due to Business Combinations

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- Definition

Net Income Loss Including Transfer from Non Controlling Interests

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- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

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- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

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- Definition

Decrease in noncontrolling interest (for example, but not limited to, redeeming or purchasing the interests of noncontrolling shareholders, issuance of shares (interests) by the non-wholly owned subsidiary to the parent entity for other than cash, and a buyback of shares (interest) by the non-wholly owned subsidiary from the noncontrolling interests).

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The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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

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Acquisitions and Dispositions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Apr. 02, 2018
Business Combination, Acquisition Related Costs	$ 232	$ 216	$ 943	$ 693
Transfers to (from) the noncontrolling interest:
Noncontrolling interest, ownership percentage by Parent (percent)	100.00%		100.00%
Net loss attributable to MDC Partners Inc.	$ (16,125)	18,493	$ (42,135)	19,180
Business acquisitions and step-up transactions			19,219
Change from net loss attributable to MDC Partners Inc. and transfers to noncontrolling interests	(11,150)	18,156	(38,326)	21,495
MDC Partners Inc. Shareholders' Deficit
Transfers to (from) the noncontrolling interest:
Net loss attributable to MDC Partners Inc.			(42,135)
Adjustments to Additional Paid in Capital, Changes due to Business Combinations	$ 4,975	$ (337)	$ 3,809	$ 2,315
Instrument [Domain]
Business Acquisition, Percentage of Voting Interests Acquired					51.00%