Basis of Presentation and Recent Developments	6 Months Ended
Basis of Presentation and Recent Developments	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Recent Developments	Basis of Presentation and Recent Developments As of June 30, 2021, MDC Partners Inc. (the “Company” or “MDC”), incorporated under the laws of Canada, is a leading provider of global marketing, advertising, activation, communications and strategic consulting solutions. Through its Networks (and underlying agencies generally referred to as “Partner Firms”), MDC delivers a wide range of customized services in order to drive growth and business performance for its clients. The accompanying consolidated financial statements include the accounts of MDC, its subsidiaries and variable interest entities for which the Company is the primary beneficiary. MDC has prepared the unaudited condensed consolidated interim 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 interim financial information on Form 10-Q. Accordingly, the financial statements have been condensed and do not include certain information and disclosures pursuant to these rules. The preparation of financial statements in conformity with GAAP requires us to make judgments, assumptions and estimates about current and future results of operations and cash flows that affect the amounts reported and disclosed. Actual results could differ from these estimates and assumptions. The consolidated results for interim periods are not necessarily indicative of results for the full year and should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 (“2020 10-K”). The Company’s business improved in the second quarter of 2021 compared to the second quarter of 2020, primarily due to recovery from the COVID-19 pandemic. Although the pandemic did not begin to impact the Company’s operations in the first quarter of 2020, it did have a significant impact on the Company’s operations in the second quarter of 2020. Therefore, the quarterly period-over-period comparisons reflect the recovery in the second quarter of 2021 and the negative impact in the second quarter of 2020. While a recovery from the pandemic is underway, economic conditions will be volatile as long as COVID-19 remains a public health threat. The Company continues to monitor developments. We will continue to monitor the worldwide public health threat, government actions to combat COVID-19 and the impact such developments may have on the overall economy, our clients and operations. If the impact of the pandemic continues to go beyond expectations, the Company believes it is well positioned through the actions implemented at the onset of the pandemic to successfully work through the effects of COVID-19 on our business. The impact of the pandemic and the corresponding actions are reflected in our judgments, assumptions and estimates in the preparation of the financial statements. The judgments, assumptions and estimates will be updated and could result in different results in the future depending on the continued impact of the COVID-19 pandemic. 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. Recent Developments On December 21, 2020, MDC and Stagwell entered into a definitive transaction agreement (as amended on June 4, 2021 and as of July 8, 2021, the “Transaction Agreement”) providing for the combination of MDC with the subsidiaries of Stagwell that own and operate a portfolio of marketing services companies (the “Stagwell Entities”). The combination and related transactions, including the domestication of MDC to a Delaware corporation, are referred to as the “Transactions.” See “Item 1. Business – Recent Developments” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020, filed on March 16, 2021, for a description of the Transactions. On July 26, 2021, the Company’s shareholders approved the Transactions, and on August 2, 2021 (the effective date), the combined company began to conduct business as Stagwell Inc. On August 3, 2021, Stagwell Inc. began to trade on the NASDAQ Stock Exchange under the ticker symbol STGW. On July 26, 2021, the Company sent a notice of redemption to the holders of its 7.50% senior notes due 2024 (the “Senior Notes”). The redemption date is scheduled for August 20, 2021 at a redemption price equal to 101.625% of the outstanding principal amount of the Senior Notes being redeemed (the “Redemption Price”), plus, accrued and unpaid interest on the principal amount of such Senior Notes (the “Redemption Payment”). The Redemption Payment is approximately $904 million, consisting of the Redemption Price of approximately $884 million (principal of $870 million and a premium of $14 million) and accrued and unpaid interest of approximately $20 million. On August 2, 2021, the Company repaid the total amount outstanding and terminated its revolving credit facility due February 3, 2022. The plan to redeem the Senior Notes and the termination of the revolving credit facility were initiated in connection with the closing of the Transactions and the plan to refinance the liquidity position of the combined company. On July 8, 2021, the Company entered into agreements with Stagwell and affiliates of The Goldman Sachs Group amending certain terms of their preference shares (see Note 10 of the Notes to the Unaudited Condensed Consolidated Financial Statements), which, among other things, reduced the accretion rate on the base liquidation preference of the combined company to zero percent per annum from and after the date that is two business days following the closing of the combination until the one year anniversary thereof. As the information provided throughout this report is historical, it primarily reflects information about the Company as of June 30, 2021, without giving effect to the Transactions or the Stagwell Entities.