Basis of Presentation and Recent Developments	12 Months Ended
Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Recent Developments	Basis of Presentation and Recent Developments The accompanying consolidated financial statements include the accounts of MDC Partners Inc. (the “Company” or “MDC”) and its subsidiaries and variable interest entities for which the Company is the primary beneficiary. References herein to “Partner Firms” generally refer to the Company’s subsidiary agencies. MDC has prepared the consolidated financial statements included herein in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”) for reporting financial information on Form 10-K. The preparation of financial statements in conformity with GAAP, which requires us to make judgments, assumptions and estimates that affect the amounts reported and disclosed. Actual results could differ from these estimates and assumptions. The accompanying financial statements reflect all adjustments, consisting of normally recurring accruals, which in the opinion of management are necessary for a fair presentation, in all material respects, of the information contained therein. Intercompany balances and transactions have been eliminated in consolidation. Certain reclassifications have been made to the prior year financial information to conform to the current year presentation. Due to changes in the composition of certain businesses and the Company’s internal management and reporting structure during 2019, reportable segment results for the 2018 and 2017 periods presented have been recast to reflect the reclassification of certain businesses between segments. See Note 21 of the Notes to the Consolidated Financial Statements included herein for further information. Nature of Operations MDC is a leading provider of global marketing, advertising, activation, communications and strategic consulting solutions. MDC’s Partner Firms deliver a wide range of customized services in order to drive growth and business performance for its clients. MDC Partners Inc., formerly MDC Corporation Inc., is incorporated under the laws of Canada. The Company commenced using the name MDC Partners Inc. on November 1, 2003 and legally changed its name through amalgamation with a wholly-owned subsidiary on January 1, 2004. The Company operates in North America, Europe, Asia, South America, and Australia. Recent Developments On February 14, 2020, the Company sold substantially all the assets and certain liabilities of Sloane and Company LLC (“Sloane”), an indirectly wholly owned subsidiary of the Company, to an affiliate of The Stagwell Group LLC (“Stagwell”), for an aggregate purchase price of approximately $26 million, consisting of cash paid at closing plus contingent deferred payments expected to be paid over the next two years. The sale resulted in a gain estimated at approximately $16 million. An affiliate of Stagwell has a minority ownership interest in the Company. Mark Penn is the CEO and Chairman of the Board of Directors (the "Board") of the Company and is also manager of Stagwell. On February 27, 2020, in connection with the centralization of our New York real estate portfolio, the Company entered into an agreement to lease space at One World Trade Center. The lease term is for approximately eleven years commencing on April 1, 2020, with rental payments totaling approximately $115 million. As part of the centralization initiative, the Company will sublease existing properties currently under lease, resulting in the recovery of a significant portion of our rent obligation under such arrangements. Effective in the first quarter of 2020, the Company reorganized its management structure resulting in the aggregation of certain Partner Firms into integrated groups (“Networks”). Mark Penn, Chief Executive Officer and Chairman of the Company, appointed key agency executives, that report directly into him, to lead each Network. In connection with the reorganization, we are assessing a change in our reportable segments, effective with the Company’s 2020 fiscal year, to align our external reporting with how we operate the Networks under our new organizational structure.

Basis of Presentation and Recent Developments

The accompanying consolidated financial statements include the accounts of MDC Partners Inc. (the “Company” or “MDC”) and its subsidiaries and variable interest entities for which the Company is the primary beneficiary. References herein to “Partner Firms” generally refer to the Company’s subsidiary agencies.

MDC has prepared the consolidated financial statements included herein in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”) for reporting financial information on Form 10-K. The preparation of financial statements in conformity with GAAP, which requires us to make judgments, assumptions and estimates that affect the amounts reported and disclosed. Actual results could differ from these estimates and assumptions.

The accompanying financial statements reflect all adjustments, consisting of normally recurring accruals, which in the opinion of management are necessary for a fair presentation, in all material respects, of the information contained therein. Intercompany balances and transactions have been eliminated in consolidation.

Certain reclassifications have been made to the prior year financial information to conform to the current year presentation.

Due to changes in the composition of certain businesses and the Company’s internal management and reporting structure during 2019, reportable segment results for the 2018 and 2017 periods presented have been recast to reflect the reclassification of certain businesses between segments. See Note 21 of the Notes to the Consolidated Financial Statements included herein for further information.

Nature of Operations

MDC is a leading provider of global marketing, advertising, activation, communications and strategic consulting solutions. MDC’s Partner Firms deliver a wide range of customized services in order to drive growth and business performance for its clients.

MDC Partners Inc., formerly MDC Corporation Inc., is incorporated under the laws of Canada. The Company commenced using the name MDC Partners Inc. on November 1, 2003 and legally changed its name through amalgamation with a wholly-owned subsidiary on January 1, 2004. The Company operates in North America, Europe, Asia, South America, and Australia.

Recent Developments

On February 14, 2020, the Company sold substantially all the assets and certain liabilities of Sloane and Company LLC (“Sloane”), an indirectly wholly owned subsidiary of the Company, to an affiliate of The Stagwell Group LLC (“Stagwell”), for an aggregate purchase price of approximately $26 million, consisting of cash paid at closing plus contingent deferred payments expected to be paid over the next two years. The sale resulted in a gain estimated at approximately $16 million. An affiliate of Stagwell has a minority ownership interest in the Company. Mark Penn is the CEO and Chairman of the Board of Directors (the "Board") of the Company and is also manager of Stagwell.

On February 27, 2020, in connection with the centralization of our New York real estate portfolio, the Company entered into an agreement to lease space at One World Trade Center. The lease term is for approximately eleven years commencing on April 1, 2020, with rental payments totaling approximately $115 million. As part of the centralization initiative, the Company will sublease existing properties currently under lease, resulting in the recovery of a significant portion of our rent obligation under such arrangements.

Effective in the first quarter of 2020, the Company reorganized its management structure resulting in the aggregation of certain Partner Firms into integrated groups (“Networks”). Mark Penn, Chief Executive Officer and Chairman of the Company, appointed key agency executives, that report directly into him, to lead each Network. In connection with the reorganization, we are assessing a change in our reportable segments, effective with the Company’s 2020 fiscal year, to align our external reporting with how we operate the Networks under our new organizational structure.