Convertible Preference Shares (Notes)	6 Months Ended
Jun. 30, 2017
Convertible Preference Shares [Abstract]
Convertible Preference Shares	8. Convertible Preference Shares On March 7, 2017 (the “Issue Date”), the Company issued 95,000 newly created Preference Shares to affiliates of The Goldman Sachs Group, Inc. (collectively, the “Purchaser”) pursuant to a $95,000 private placement. The Company received proceeds of approximately $90,220, net of fees and estimated expenses, which were primarily used to pay down existing debt under the Company’s credit facility and for general corporate purposes. In connection with the closing of the transaction, effective March 7, 2017, the Company increased the size of its Board of Directors (the “Board”) to seven members and appointed one nominee designated by the Purchaser. Except as required by law, the Preference Shares do not have voting rights, and are not redeemable at the option of the Purchaser. The holders of the Preference Shares have the right to convert their Preference Shares, in whole at any time and from time to time, and in part at any time and from time to time after the ninetieth day following the original issuance date of the Preference Shares, into a number of Class A subordinate voting shares of the Company (the “Class A Shares”) equal to the then-applicable liquidation preference divided by the applicable conversion price at such time (the “Conversion Price”). The initial liquidation per share preference of each Preference Share is $1,000. The initial Conversion Price will be $10.00 per Preference Share, subject to customary adjustments for share splits and combinations, dividends, recapitalizations and other matters, including weighted average anti-dilution protection for certain issuances of equity or equity-linked securities. The Preference Shares’ liquidation preference accretes at 8.0% per annum, compounded quarterly until the five-year anniversary of the Issue Date. During the three and six months ended June 30, 2017, the Preference Shares accreted at a monthly rate of approximately $6.70 per Preference Share, for total accretion of $2,417, bringing the aggregate liquidation preference to $97,417 as of June 30, 2017. The accretion is considered in the calculation of net income (loss) attributable to MDC Partners Inc. common shareholders. See Notes 2 and 3. Holders of the Preference Shares are entitled to dividends in an amount equal to any dividends that would otherwise have been payable on the Class A Shares issued upon conversion of the Preference Shares. The Preference Shares are convertible at the Company’s option (i) on and after the two-year anniversary of the Issue Date, if the closing trading price of the Class A Shares over a specified period prior to conversion is at least 125% of the Conversion Price or (ii) after the fifth anniversary of the Issue Date, if the closing trading price of the Class A Shares over a specified period prior to conversion is at least equal to the Conversion Price. Following certain change in control transactions of the Company in which holders of Preference Shares are not entitled to receive cash or qualifying listed securities with a value at least equal to the liquidation preference plus accrued and unpaid dividends, (i) holders will be entitled to cash dividends on the liquidation preference at an increasing rate (beginning at 7%), and (ii) the Company will have a right to redeem the Preference Shares for cash at the greater of their liquidation preference plus accrued and unpaid dividends or their as-converted value.

8. Convertible Preference Shares

On March 7, 2017 (the “Issue Date”), the Company issued 95,000 newly created Preference Shares to affiliates of The Goldman Sachs Group, Inc. (collectively, the “Purchaser”) pursuant to a $95,000 private placement. The Company received proceeds of approximately $90,220, net of fees and estimated expenses, which were primarily used to pay down existing debt under the Company’s credit facility and for general corporate purposes. In connection with the closing of the transaction, effective March 7, 2017, the Company increased the size of its Board of Directors (the “Board”) to seven members and appointed one nominee designated by the Purchaser. Except as required by law, the Preference Shares do not have voting rights, and are not redeemable at the option of the Purchaser.

The holders of the Preference Shares have the right to convert their Preference Shares, in whole at any time and from time to time, and in part at any time and from time to time after the ninetieth day following the original issuance date of the Preference Shares, into a number of Class A subordinate voting shares of the Company (the “Class A Shares”) equal to the then-applicable liquidation preference divided by the applicable conversion price at such time (the “Conversion Price”). The initial liquidation per share preference of each Preference Share is $1,000. The initial Conversion Price will be $10.00 per Preference Share, subject to customary adjustments for share splits and combinations, dividends, recapitalizations and other matters, including weighted average anti-dilution protection for certain issuances of equity or equity-linked securities.

The Preference Shares’ liquidation preference accretes at 8.0% per annum, compounded quarterly until the five-year anniversary of the Issue Date. During the three and six months ended June 30, 2017, the Preference Shares accreted at a monthly rate of approximately $6.70 per Preference Share, for total accretion of $2,417, bringing the aggregate liquidation preference to $97,417 as of June 30, 2017. The accretion is considered in the calculation of net income (loss) attributable to MDC Partners Inc. common shareholders. See Notes 2 and 3.

Holders of the Preference Shares are entitled to dividends in an amount equal to any dividends that would otherwise have been payable on the Class A Shares issued upon conversion of the Preference Shares. The Preference Shares are convertible at the Company’s option (i) on and after the two-year anniversary of the Issue Date, if the closing trading price of the Class A Shares over a specified period prior to conversion is at least 125% of the Conversion Price or (ii) after the fifth anniversary of the Issue Date, if the closing trading price of the Class A Shares over a specified period prior to conversion is at least equal to the Conversion Price.

Following certain change in control transactions of the Company in which holders of Preference Shares are not entitled to receive cash or qualifying listed securities with a value at least equal to the liquidation preference plus accrued and unpaid dividends, (i) holders will be entitled to cash dividends on the liquidation preference at an increasing rate (beginning at 7%), and (ii) the Company will have a right to redeem the Preference Shares for cash at the greater of their liquidation preference plus accrued and unpaid dividends or their as-converted value.