Stagwell (STGW) 10-Q 11 May 20 2020 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2020	Apr. 17, 2020
Document Information [Line Items]
Entity Registrant Name	MDC PARTNERS INC
Entity Central Index Key	0000876883
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Current Reporting Status	Yes
Document Type	10-Q
Entity Small Business	true
Document Fiscal Year Focus	2020
Document Period End Date	Mar. 31, 2020
Document Fiscal Period Focus	Q1
Amendment Flag	false
Common Class A
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		72,479,423
Common Class B
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		3,743

UNAUDITED CONDENSED CONSOLIDATE

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue:
Services	$ 327,742	$ 328,791
Operating expenses:
Cost of services sold	222,693	237,153
Office and general expenses	66,353	67,118
Depreciation and amortization	9,206	8,838
Other asset impairment	161	0
Costs and Expenses, Total	298,413	313,109
Operating income	29,329	15,682
Other income (expense):
Interest expense and finance charges, net	(15,612)	(16,760)
Other, net	16,334	(3,383)
Foreign exchange gain (loss)	(14,757)	5,442
Nonoperating Income (Expense), Total	(14,035)	(14,701)
Income before income taxes and equity in earnings of non-consolidated affiliates	15,294	981
Income tax expense	13,500	748
Income before equity in earnings of non-consolidated affiliates	1,794	233
Equity in earnings of non-consolidated affiliates	0	83
Net income	1,794	316
Net income attributable to the noncontrolling interest	(791)	(429)
Net income (loss) attributable to MDC Partners Inc.	1,003	(113)
Net loss attributable to MDC Partners Inc. common shareholders	$ (2,437)	$ (2,496)
Basic and diluted
Earnings per share, basic	$ (0.03)	$ (0.04)
Earnings per share, diluted	$ (0.03)	$ (0.04)
Weighted Average Number of Common Shares Outstanding:
Weighted Average Number of Shares Outstanding, Basic	72,397,661	60,258,102
Weighted Average Number of Shares Outstanding, Diluted	72,397,661	60,258,102
Series 4 Convertible Preferred Stock [Domain] | Preferred Stock
Other income (expense):
Accretion on and net income allocated to convertible preference shares	$ (3,440)	$ (2,383)

UNAUDITED CONSOLIDATED STATEMEN

UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Comprehensive income (loss)
Net loss	$ 1,794	$ 316
Other comprehensive income (loss), net of applicable tax:
Foreign currency translation adjustment	7,429	(4,659)
Other comprehensive income (loss)	7,429	(4,659)
Comprehensive income (loss) for the period	9,223	(4,343)
Comprehensive income attributable to the noncontrolling interests	(282)	(780)
Comprehensive income (loss) attributable to MDC Partners Inc.	$ 8,941	$ (5,123)

UNAUDITED CONDENSED CONSOLIDA_2

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Current Assets:
Cash and cash equivalents	$ 221,102	$ 106,933
Accounts receivable, less allowance for doubtful accounts of $2,111 and $3,304	407,311	450,403
Expenditures billable to clients	22,763	30,133
Other current assets	44,689	35,613
Total Current Assets	695,865	623,082
Fixed assets, at cost, less accumulated depreciation of $132,174 and $129,579	75,767	81,054
Right-of-use assets - operating leases	216,194	223,622
Goodwill	725,390	740,674
Other intangible assets, net	50,640	54,893
Deferred tax assets	77,378	85,988
Other assets	29,622	30,179
Total Assets	1,870,856	1,839,492
Current Liabilities:
Accounts payable	153,491	200,148
Accruals and other liabilities	325,826	353,575
Advance billings	146,803	171,742
Current portion of lease liabilities - operating leases	48,022	48,659
Current portion of deferred acquisition consideration	46,337	45,521
Total Current Liabilities	720,479	819,645
Long-term debt	1,014,260	887,630
Long-term portion of deferred acquisition consideration	26,399	29,699
Long-term lease liabilities - operating leases	211,254	219,163
Other liabilities	35,523	25,771
Total Liabilities	2,007,915	1,981,908
Redeemable Noncontrolling Interests	35,698	36,973
Commitments, Contingencies, and Guarantees (Note 9)
Shareholders’ Deficit:
Convertible preference shares, 145,000 authorized, issued and outstanding at March 31, 2020 and December 31, 2019	152,746	152,746
Common stock and other paid-in capital	99,587	101,469
Accumulated deficit	(468,508)	(469,593)
Accumulated other comprehensive (loss) income	3,669	(4,269)
MDC Partners Inc. Shareholders' Deficit	(212,506)	(219,647)
Noncontrolling interests	39,749	40,258
Total Shareholders' Deficit	(172,757)	(179,389)	$ (174,273)
Total Liabilities, Redeemable Noncontrolling Interests and Shareholders' Deficit	$ 1,870,856	$ 1,839,492

UNAUDITED CONDENSED CONSOLIDA_3

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 2,111	$ 3,304
Fixed assets, accumulated depreciation	$ 132,174	$ 129,579
Preference shares, authorized (in shares)	145,000	95,000
Preference shares, issued (in shares)	145,000	95,000
Preference shares, outstanding (in shares)	145,000	95,000

UNAUDITED CONDENSED CONSOLIDA_4

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ 1,794	$ 316
Adjustments to reconcile net income to cash used in operating activities:
Stock-based compensation	3,070	2,972
Depreciation and amortization	9,206	8,838
Other asset impairment	161	0
Adjustment to deferred acquisition consideration	(4,600)	(7,643)
Deferred income taxes	8,511	748
Other	4,489	(2,608)
Changes in working capital:
Accounts receivable	41,148	(29,957)
Expenditures billable to clients	7,370	(4,294)
Prepaid expenses and other current assets	(3,385)	(3,373)
Accounts payable, accruals and other current liabilities	(62,120)	(75,105)
Acquisition related payments	(782)	(3,657)
Advance billings	(24,816)	32,563
Net cash used in operating activities	(19,954)	(81,200)
Cash flows from investing activities:
Capital expenditures	(1,546)	(3,606)
Proceeds from sale of assets	18,920	23,050
Acquisitions, net of cash acquired	(729)	(1,050)
Other	0	(293)
Net cash provided by investing activities	16,645	18,101
Cash flows from financing activities:
Acquisition related payments	(750)	0
Other	(4,608)	(1,536)
Net cash provided by financing activities	119,642	60,753
Effect of exchange rate changes on cash, cash equivalents, and cash held in trusts	(2,164)	(576)
Net increase (decrease) in cash and cash equivalents, including cash classified within current assets held for sale	114,169	(2,922)
Change in cash and cash equivalents held in trusts classified within held for sale	0	(3,307)
Change in cash and cash equivalents classified within assets held for sale	0	1,728
Net increase (decrease) in cash and cash equivalents	114,169	(4,501)
Cash and cash equivalents at beginning of period	106,933	30,873
Cash and cash equivalents at end of period	221,102	26,372
Supplemental disclosures:
Cash income taxes paid	849	1,677
Cash interest paid	145	1,629
Wells Fargo Capital Finance, LLC | Revolving Credit Facility
Cash flows from financing activities:
Net increase (decrease) in revolving credit facility	125,000	(35,340)
Series 4 Convertible Preferred Stock
Cash flows from financing activities:
Proceeds from issuance of common and convertible preference shares, net of issuance costs	$ 0	$ 97,629

UNAUDITED CONDENSED CONSOLIDA_5

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' DEFICIT - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit	AOCI Attributable to Parent [Member]	MDC Partners Inc. Shareholders' Deficit	Noncontrolling Interest	Series 4 Convertible Preferred Stock [Member]Convertible Preferred Stock
Balance at Dec. 31, 2018	$ (246,967)	$ 90,123		$ 58,579	$ (464,903)	$ 4,720	$ (311,481)	$ 64,514
Balance (in shares) at Dec. 31, 2018									95,000,000
Common stock, balance (in shares) at Dec. 31, 2018			57,521,323
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss attributable to MDC Partners Inc.	(113)				(113)		(113)
Other comprehensive income (loss)	(4,659)					(5,010)	(5,010)	351
Issuance of common and preference shares (in shares)		50,000,000	14,285,714
Issuance of common and convertible preference shares	97,629	$ 61,994		35,635			97,629
Issuance of restricted stock (in shares)			117,000
Shares acquired and cancelled	(56)			(56)			(56)
Shares acquired and cancelled (in shares)			(34,016)
Stock-based compensation	(1,291)			(1,291)			(1,291)
Changes in redemption value of redeemable noncontrolling interests	5,919			5,919			5,919
Changes in ownership interest	(24,735)			(93)			(93)	(24,642)
Business acquisitions and step-up transactions, net of tax	0						0
Balance at Mar. 31, 2019	(174,273)	152,117		98,693	(465,016)	(290)	(214,496)	40,223
Balance (in shares) at Mar. 31, 2019									145,000,000
Common stock, balance (in shares) at Mar. 31, 2019			71,890,021
Balance at Dec. 31, 2019	(179,389)	152,746		101,469	(469,593)	(4,269)	(219,647)	40,258
Balance (in shares) at Dec. 31, 2019									145,000,000
Common stock, balance (in shares) at Dec. 31, 2019			72,154,603
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss attributable to MDC Partners Inc.	1,003						1,003
Other comprehensive income (loss)	7,429					7,938	7,938	(509)
Issuance of restricted stock	0
Issuance of restricted stock (in shares)			587,227
Shares acquired and cancelled	(637)			(637)			(637)
Shares acquired and cancelled (in shares)			(258,664)
Stock-based compensation	476			476			476
Changes in redemption value of redeemable noncontrolling interests	(1,218)			(1,218)			(1,218)
Business acquisitions and step-up transactions, net of tax	(503)			(503)			(503)
Other	82			0	82	0	82	0
Balance at Mar. 31, 2020	$ (172,757)	$ 152,746		$ 99,587	$ (468,508)	$ 3,669	$ (212,506)	$ 39,749
Balance (in shares) at Mar. 31, 2020									145,000,000
Common stock, balance (in shares) at Mar. 31, 2020			72,483,166

Basis of Presentation and Recen

Basis of Presentation and Recent Developments	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Recent Developments	asis of Presentation and Recent Developments 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, 2019 (“2019 Form 10-K”). The Company expects the effects of the COVID-19 pandemic to negatively impact its results of operations, cash flows and financial position. While it is difficult to predict the full scale of the impact, the Company has been taking actions to address the impact of the pandemic, such as working closely with our clients, reducing our expenses and monitoring liquidity. The impact of the pandemic and the corresponding actions were reflected into our judgments, assumptions and estimates to prepare the financial statements. However, if the duration of the COVID-19 pandemic is longer and the operational impact is greater than estimated, the judgments, assumptions and estimates will be updated and could result in different results in the future. 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. The Company reorganized its management structure in 2020 which resulted in a change to our reportable segments. Prior periods presented have been recast to reflect the change in reportable segments. See Note 14 of the Notes to the Unaudited Condensed Consolidated Financial Statements included herein for further information. Recent Developments In April 2020, the Company repurchased approximately $30,000 of the total $900,000 6.50% Notes due in May 2024, at a weighted average price equal to 74% of the principal amount totaling approximately $22,000 , and accrued interest of approximately $946 . As a result of the repurchase, we will recognize an estimated extinguishment gain of $8,000 .

Acquisitions and Dispositions

Acquisitions and Dispositions	3 Months Ended
	Mar. 31, 2020
Business Combinations [Abstract]
Acquisitions and Dispositions	Acquisitions and Dispositions 2020 Acquisition On March 19, 2020, the Company acquired the remaining 22.5% ownership interest of KWT Global it did not already own for an aggregate purchase price of $2,118 , comprised of a closing cash payment of $729 and contingent deferred acquisition payments with an estimated present value at the acquisition date of $1,389 . The contingent deferred payments are based on the financial results of the underlying business from 2019 to 2020 with final payment due in 2021. As a result of the transaction, the Company reduced redeemable noncontrolling interests by $1,615 . The difference between the purchase price and the redeemable noncontrolling interest of $503 was recorded in Common stock and other paid-in capital in the Unaudited Condensed Consolidated Balance Sheets . 2020 Disposition 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 $26,000 , 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 of approximately $16,131 , which is included in Other, net within the Unaudited Condensed Consolidated Statement of Operations . Sloane was included within Allison & Partners which is included within the All Other category. 2019 Acquisitions On November 15, 2019, the Company acquired the remaining 35% ownership interest of Laird + Partners it did not already own for an aggregate purchase price of $2,389 , comprised of a closing cash payment of $1,588 and contingent deferred acquisition payments with an estimated present value at the acquisition date of $801 . The contingent deferred payments are based on the financial results of the underlying business from 2018 to 2020 with final payment due in 2021. As a result of the transaction, the Company reduced redeemable noncontrolling interests by $5,045 . The difference between the purchase price and the redeemable noncontrolling interest of $2,656 was recorded in Common stock and other paid-in capital in the Unaudited Condensed Consolidated Balance Sheets . Effective April 1, 2019, the Company acquired the remaining 35% ownership interest of HPR Partners LLC (Hunter) it did not already own for an aggregate purchase price of $10,234 , comprised of a closing cash payment of $3,890 and additional contingent deferred acquisition payments with an estimated present value at the acquisition date of $6,344 . The contingent deferred payments are based on the financial results of the underlying business from 2018 to 2020 with final payment due in 2021. As a result of the transaction, the Company reduced redeemable noncontrolling interests by $9,486 . The difference between the purchase price and the redeemable noncontrolling interest of $745 was recorded in Common stock and other paid-in capital in the Unaudited Condensed Consolidated Balance Sheets . 2019 Disposition On March 8, 2019, the Company consummated the sale of Kingsdale, an operating segment with operations in Toronto and New York City that provides shareholder advisory services. As consideration for the sale, the Company received cash plus the assumption of certain liabilities totaling approximately $50,000 in the aggregate. The sale resulted in a loss of approximately $3,000 , which was included in Other, net within the Unaudited Condensed Consolidated Statement of Operations . Deferred Acquisition Consideration Deferred acquisition consideration on the balance sheet consists of deferred obligations related to contingent and fixed purchase price payments, and to a lesser extent, contingent and fixed retention payments tied to continued employment of specific personnel. Contingent deferred acquisition consideration is recorded at the acquisition date fair value and adjusted at each reporting period through operating income, for contingent purchase price payments, or net interest expense, for fixed purchase price payments. The Company accounts for retention payments through operating income as stock-based compensation over the required retention period. The following table presents changes in contingent deferred acquisition consideration, which is measured at fair value on a recurring basis using significant unobservable inputs, and a reconciliation to the amounts reported on the balance sheets as of March 31, 2020 and December 31, 2019 . March 31, December 31, 2020 2019 Beginning Balance of contingent payments $ 74,671 $ 82,598 Payments (1,125 ) (30,719 ) Redemption value adjustments (1) (2,575 ) 15,451 Additions - acquisitions and step-up transactions 1,389 7,145 Other (2) (185 ) 196 Ending Balance of contingent payments $ 72,175 $ 74,671 Fixed payments 561 549 $ 72,736 $ 75,220 (1) Redemption value adjustments are fair value changes from the Company’s initial estimates of deferred acquisition payments and stock-based compensation charges relating to acquisition payments that are tied to continued employment. Redemption value adjustments are recorded within cost of services sold and office and general expenses on the Unaudited Condensed Consolidated Statement of Operations . (2) Other primarily consists of translation adjustments. The following table presents the impact to the Company’s statement of operations due to the redemption value adjustments for the contingent deferred acquisition consideration: Three Months Ended March 31, 2020 2019 Income attributable to fair value adjustments $ (4,600 ) $ (7,643 ) Stock-based compensation 2,025 809 Redemption value adjustments $ (2,575 ) $ (6,834 )

Revenue

Revenue	3 Months Ended
	Mar. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue	Revenue The Company’s revenue recognition policies are established in accordance with ASC 606, and accordingly, revenue is recognized when control of the promised goods or services is transferred to our clients, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. The MDC network provides an extensive range of services to our clients offering a variety of marketing and communication capabilities including strategy, creative and production for advertising campaigns across a variety of platforms (print, digital, social media, television broadcast), public relations services including strategy, editorial, crisis support or issues management, media training, influencer engagement and events management. We also provide media buying and planning across a range of platforms (out-of-home, paid search, social media, lead generation, programmatic, television broadcast), experiential marketing and application/website design and development. The primary source of the Company’s revenue is from agency arrangements in the form of fees for services performed, commissions, and from performance incentives or bonuses, depending on the terms of the client contract. In all circumstances, revenue is only recognized when collection is reasonably assured. Certain of the Company’s contractual arrangements have more than one performance obligation. For such arrangements, revenue is allocated to each performance obligation based on its relative stand-alone selling price. Stand-alone selling prices are determined based on the prices charged to clients or using expected cost plus margin. The determination of our performance obligations is specific to the services included within each contract. Based on a client’s requirements within the contract, and how these services are provided, multiple services could represent separate performance obligations or be combined and considered one performance obligation. Contracts that contain services that are not significantly integrated or interdependent, and that do not significantly modify or customize each other, are considered separate performance obligations. Typically, we consider media planning, media buying, creative (or strategy), production and experiential marketing services to be separate performance obligations if included in the same contract as each of these services can be provided on a stand-alone basis, and do not significantly modify or customize each other. Public relations services and application/website design and development are typically each considered one performance obligation as there is a significant integration of these services into a combined output. We typically satisfy our performance obligations over time, as services are performed. Fees for services are typically recognized using input methods (direct labor hours, materials and third-party costs) that correspond with efforts incurred to date in relation to total estimated efforts to complete the contract. Point in time recognition primarily relates to certain commission-based contracts, which are recognized upon the placement of advertisements in various media when the Company has no further performance obligation. Revenue is recognized net of sales and other taxes due to be collected and remitted to governmental authorities. The Company’s contracts typically provide for termination by either party within 30 to 90 days. Although payment terms vary by client, they are typically within 30 to 60 days. In addition, the Company generally has the right to payment for all services provided through the end of the contract or termination date. Within each contract, we identify whether the Company is principal or agent at the performance obligation level. In arrangements where the Company has substantive control over the service before transferring it to the client, and is primarily responsible for integrating the services into the final deliverables, we act as principal. In these arrangements, revenue is recorded at the gross amount billed. Accordingly, for these contracts the Company has included reimbursed expenses in revenue. In other arrangements where a third-party supplier, rather than the Company, is primarily responsible for the integration of services into the final deliverables, and thus the Company is solely arranging for the third-party supplier to provide these services to our client, we generally act as agent and record revenue equal to the net amount retained, when the fee or commission is earned. The role of MDC’s agencies under a production services agreement that is to facilitate a client’s purchasing of production capabilities from a third-party production company in accordance with the client’s strategy and guidelines. The obligation of MDC’s agencies under media buying services is to negotiate and purchase advertising media from a third-party media vendor on behalf of a client to execute its media plan. We do not obtain control prior to transferring these services to our clients; therefore, we primarily act as agent for production and media buying services. A small portion of the Company’s contractual arrangements with clients include performance incentive provisions, which allow the Company to earn additional revenues as a result of its performance relative to both quantitative and qualitative goals. Incentive compensation is primarily estimated using the most likely amount method and is included in revenue up to the amount that is not expected to result in a reversal of a significant amount of cumulative revenue recognized. We recognize revenue related to performance incentives as we satisfy the performance obligation to which the performance incentives are related. Disaggregated Revenue Data The Company provides a broad range of services to a large base of clients across the full spectrum of industry verticals on a global basis. The primary source of revenue is from agency arrangements in the form of fees for services performed, commissions, and from performance incentives or bonuses. Certain clients may engage with the Company in various geographic locations, across multiple disciplines, and through multiple Partner Firms. Representation of a client rarely means that MDC handles marketing communications for all brands or product lines of the client in every geographical location. The Company maintains separate, independent operating companies to enable it to effectively manage potential conflicts of interest by representing competing clients across the Company. The following table presents revenue disaggregated by client industry vertical for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, Industry Reportable Segment 2020 2019 Food & Beverage All $ 58,091 $ 66,663 Retail All 36,303 32,580 Consumer Products All 39,769 35,001 Communications All 41,045 39,798 Automotive All 25,192 18,191 Technology All 25,535 26,616 Healthcare All 24,066 23,297 Financials All 24,005 25,126 Transportation and Travel/Lodging All 20,486 17,441 Other All 33,250 44,078 $ 327,742 $ 328,791 MDC has historically largely focused where the Company was founded in North America, the largest market for its services in the world. MDC’s Partner Firms are located in the United States, Canada, and an additional eleven countries around the world. In the past, some clients have responded to weakening economic conditions with reductions to their marketing budgets, which included discretionary components that are easier to reduce in the short term than other operating expenses. The following table presents revenue disaggregated by geography for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, Geographic Location Reportable Segment 2020 2019 United States All $ 264,561 $ 263,017 Canada All 18,256 22,378 Other All 44,925 43,396 $ 327,742 $ 328,791 Contract assets and liabilities Contract assets consist of fees and reimbursable outside vendor costs incurred on behalf of clients when providing advertising, marketing and corporate communications services that have not yet been invoiced to clients. Unbilled service fees were $76,753 and $66,119 at March 31, 2020 and December 31, 2019 , respectively, and are included as a component of accounts receivable on the Unaudited Condensed Consolidated Balance Sheets . Outside vendor costs incurred on behalf of clients which have yet to be invoiced were $22,763 and $30,133 at March 31, 2020 and December 31, 2019 , respectively, and are included on the Unaudited Condensed Consolidated Balance Sheets as expenditures billable to clients. Such amounts are invoiced to clients at various times over the course of providing services. Contract liabilities consist of fees billed to clients in excess of fees recognized as revenue and are classified as advance billings on the Company’s Unaudited Condensed Consolidated Balance Sheets . Advance billings at March 31, 2020 and December 31, 2019 were $146,803 and $171,742 , respectively. The decrease in the advance billings balance of $24,939 for the three months ended March 31, 2020 was primarily driven by cash payments received or due in advance of satisfying our performance obligations, offset by $104,937 of revenues recognized that were included in the advance billings balances as of December 31, 2019 and reductions due to the incurrence of third-party costs. Changes in the contract asset and liability balances during the three months ended March 31, 2020 and December 31, 2019 were not materially impacted by write offs, impairment losses or any other factors. The majority of our contracts are for periods of one year or less. For those contracts with a term of more than one year, we had approximately $35,771 of unsatisfied performance obligations as of March 31, 2020 , of which we expect to recognize approximately 87% in 2020, 11% in 2021 and 2% in 2022.

Income (Loss) Per Common Share

Income (Loss) Per Common Share	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Loss Per Common Share	Income (Loss) Per Common Share The following table sets forth the computation of basic and diluted income (loss) per common share: Three Months Ended March 31, 2020 2019 Numerator: Net income (loss) attributable to MDC Partners Inc. $ 1,003 $ (113 ) Accretion on convertible preference shares (3,440 ) (2,383 ) Net loss attributable to MDC Partners Inc. common shareholders $ (2,437 ) $ (2,496 ) Denominator: Basic weighted average number of common shares outstanding 72,397,661 60,258,102 Diluted weighted average number of common shares outstanding 72,397,661 60,258,102 Basic $ (0.03 ) $ (0.04 ) Diluted $ (0.03 ) $ (0.04 ) Anti-dilutive stock awards 2,835,770 1,633,464 Restricted stock and restricted stock unit awards of 2,203,717 and 257,280 as of March 31, 2020 and 2019 respectively, are excluded from the computation of diluted income (loss) per common share because the performance contingency necessary for vesting has not been met as of the reporting date or all the terms and conditions to establish a grant date were not yet known. In addition, there were 145,000 Preference Shares outstanding which were convertible into 27,189,411 and 25,118,813 Class A common shares at March 31, 2020 and 2019 , respectively. These Preference Shares were anti-dilutive for each period presented in the table above and are therefore excluded from the diluted income (loss) per common share calculation.

Deferred Acquisition Considerat

Deferred Acquisition Consideration	3 Months Ended
	Mar. 31, 2020
Business Combinations [Abstract]
Deferred Acquisition Consideration	Acquisitions and Dispositions 2020 Acquisition On March 19, 2020, the Company acquired the remaining 22.5% ownership interest of KWT Global it did not already own for an aggregate purchase price of $2,118 , comprised of a closing cash payment of $729 and contingent deferred acquisition payments with an estimated present value at the acquisition date of $1,389 . The contingent deferred payments are based on the financial results of the underlying business from 2019 to 2020 with final payment due in 2021. As a result of the transaction, the Company reduced redeemable noncontrolling interests by $1,615 . The difference between the purchase price and the redeemable noncontrolling interest of $503 was recorded in Common stock and other paid-in capital in the Unaudited Condensed Consolidated Balance Sheets . 2020 Disposition 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 $26,000 , 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 of approximately $16,131 , which is included in Other, net within the Unaudited Condensed Consolidated Statement of Operations . Sloane was included within Allison & Partners which is included within the All Other category. 2019 Acquisitions On November 15, 2019, the Company acquired the remaining 35% ownership interest of Laird + Partners it did not already own for an aggregate purchase price of $2,389 , comprised of a closing cash payment of $1,588 and contingent deferred acquisition payments with an estimated present value at the acquisition date of $801 . The contingent deferred payments are based on the financial results of the underlying business from 2018 to 2020 with final payment due in 2021. As a result of the transaction, the Company reduced redeemable noncontrolling interests by $5,045 . The difference between the purchase price and the redeemable noncontrolling interest of $2,656 was recorded in Common stock and other paid-in capital in the Unaudited Condensed Consolidated Balance Sheets . Effective April 1, 2019, the Company acquired the remaining 35% ownership interest of HPR Partners LLC (Hunter) it did not already own for an aggregate purchase price of $10,234 , comprised of a closing cash payment of $3,890 and additional contingent deferred acquisition payments with an estimated present value at the acquisition date of $6,344 . The contingent deferred payments are based on the financial results of the underlying business from 2018 to 2020 with final payment due in 2021. As a result of the transaction, the Company reduced redeemable noncontrolling interests by $9,486 . The difference between the purchase price and the redeemable noncontrolling interest of $745 was recorded in Common stock and other paid-in capital in the Unaudited Condensed Consolidated Balance Sheets . 2019 Disposition On March 8, 2019, the Company consummated the sale of Kingsdale, an operating segment with operations in Toronto and New York City that provides shareholder advisory services. As consideration for the sale, the Company received cash plus the assumption of certain liabilities totaling approximately $50,000 in the aggregate. The sale resulted in a loss of approximately $3,000 , which was included in Other, net within the Unaudited Condensed Consolidated Statement of Operations . Deferred Acquisition Consideration Deferred acquisition consideration on the balance sheet consists of deferred obligations related to contingent and fixed purchase price payments, and to a lesser extent, contingent and fixed retention payments tied to continued employment of specific personnel. Contingent deferred acquisition consideration is recorded at the acquisition date fair value and adjusted at each reporting period through operating income, for contingent purchase price payments, or net interest expense, for fixed purchase price payments. The Company accounts for retention payments through operating income as stock-based compensation over the required retention period. The following table presents changes in contingent deferred acquisition consideration, which is measured at fair value on a recurring basis using significant unobservable inputs, and a reconciliation to the amounts reported on the balance sheets as of March 31, 2020 and December 31, 2019 . March 31, December 31, 2020 2019 Beginning Balance of contingent payments $ 74,671 $ 82,598 Payments (1,125 ) (30,719 ) Redemption value adjustments (1) (2,575 ) 15,451 Additions - acquisitions and step-up transactions 1,389 7,145 Other (2) (185 ) 196 Ending Balance of contingent payments $ 72,175 $ 74,671 Fixed payments 561 549 $ 72,736 $ 75,220 (1) Redemption value adjustments are fair value changes from the Company’s initial estimates of deferred acquisition payments and stock-based compensation charges relating to acquisition payments that are tied to continued employment. Redemption value adjustments are recorded within cost of services sold and office and general expenses on the Unaudited Condensed Consolidated Statement of Operations . (2) Other primarily consists of translation adjustments. The following table presents the impact to the Company’s statement of operations due to the redemption value adjustments for the contingent deferred acquisition consideration: Three Months Ended March 31, 2020 2019 Income attributable to fair value adjustments $ (4,600 ) $ (7,643 ) Stock-based compensation 2,025 809 Redemption value adjustments $ (2,575 ) $ (6,834 )

Leases

Leases	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Leases	Leases The Company leases office space in North America, Europe, Asia, South America, and Australia. This space is primarily used for office and administrative purposes by the Company’s employees in performing professional services. These leases are classified as operating leases and expire between years 2020 through 2032. The Company’s finance leases are immaterial. The Company’s leasing policies are established in accordance with ASC 842, and accordingly, the Company recognizes on the balance sheet at the time of lease commencement a right-of-use lease asset and a lease liability, initially measured at the present value of the lease payments. Right-of-use lease assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. All right-of-use lease assets are reviewed for impairment. As the Company’s implicit rate in its leases is not readily determinable, in determining the present value of lease payments, the Company uses its incremental borrowing rate based on the information available at the commencement date. Lease payments included in the measurement of the lease liability are comprised of noncancelable lease payments, payments based upon an index or rate, payments for optional renewal periods where it is reasonably certain the renewal period will be exercised, and payments for early termination options unless it is reasonably certain the lease will not be terminated early. Lease costs are recognized in the Consolidated Statement of Operations over the lease term on a straight-line basis. Leasehold improvements are depreciated on a straight-line basis over the lesser of the term of the related lease or the estimated useful life of the asset. Some of the Company’s leases contain variable lease payments, including payments based upon an index or rate. Variable lease payments based upon an index or rate are initially measured using the index or rate in effect at the lease commencement date and are included within the lease liabilities. Lease liabilities are not remeasured as a result of changes in the index or rate, rather changes in these types of payments are recognized in the period in which the obligation for those payments is incurred. In addition, some of our leases contain variable payments for utilities, insurance, real estate tax, repairs and maintenance, and other variable operating expenses. Such amounts are not included in the measurement of the lease liability and are recognized in the period when the facts and circumstances on which the variable lease payments are based upon occur. The Company’s leases include options to extend or renew the lease through 2040. The renewal and extension options are not included in the lease term as the Company is not reasonably certain that it will exercise its option. From time to time, the Company enters into sublease arrangements both with unrelated third-parties and with our partner agencies. These leases are classified as operating leases and expire between years 2020 through 2032. Sublease income is recognized over the lease term on a straight-line basis. Currently, the Company subleases office space in North America, Europe and Australia. As of March 31, 2020 , the Company has entered into three operating leases for which the commencement date has not yet occurred as the premises are in the process of being prepared for occupancy by the landlord. One of the operating leases is related to the Company’s agreement, entered into on February 27, 2020, to lease space at One World Trade Center in connection with the centralization of our New York real estate portfolio. The lease term is for approximately eleven years, with rental payments totaling approximately $112,000 , net of landlord reimbursements. As part of the centralization initiative, the Company will sublease existing properties currently under lease, resulting in the recovery of a portion of our rent obligation under such arrangements. Accordingly, these three leases represent an obligation of the Company that is not reflected within the Unaudited Consolidated Balance Sheet as of March 31, 2020 . The aggregate future liability related to these leases is approximately $124,233 . The discount rate used for leases accounted for under ASC 842 is the Company’s collateralized credit adjusted borrowing rate. The following table presents lease costs and other quantitative information for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, 2020 2019 Lease Cost: Operating lease cost $ 16,391 $ 16,441 Variable lease cost 4,655 4,964 Sublease rental income (2,805 ) (1,599 ) Total lease cost $ 18,241 $ 19,806 Additional information: Cash paid for amounts included in the measurement of lease liabilities for operating leases Operating cash flows $ 17,635 $ 15,652 Right-of-use assets obtained in exchange for operating lease liabilities $ 7,119 $ 256,818 Weighted average remaining lease term (in years) - Operating leases 7.0 7.3 Weighted average discount rate - Operating leases 8.7 8.7 In the three months ended March 31, 2020 , the Company recorded an impairment charge of $161 to reduce the carrying value of a right-of-use lease asset of one of its agencies within its Integrated Agencies Network reportable segment. The Company evaluated the facts and circumstances related to the use of the asset which indicated that it may not be recoverable. Using adjusted quoted market prices to develop expected future cash flows, it was determined that the fair value of the asset was less than its carrying value. This impairment charge is included in Other asset impairment within the Unaudited Condensed Consolidated Statement of Operations . In the three months ended March 31, 2019 , the Company did not record any impairment charge to reduce the carrying value of its right-of-use lease assets or related leasehold improvements. Operating lease expense is included in office and general expenses in the Unaudited Condensed Consolidated Statement of Operations . The Company’s lease expense for leases with a term of 12 months or less is immaterial. The following table presents minimum future rental payments under the Company’s leases at March 31, 2020 and their reconciliation to the corresponding lease liabilities: Maturity Analysis Remaining 2020 $ 52,025 2021 59,901 2022 49,774 2023 44,573 2024 38,111 Thereafter 103,505 Total 347,889 Less: Present value discount (88,613 ) Lease liability $ 259,276

Debt

Debt	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Debt	Debt As of March 31, 2020 and December 31, 2019 , the Company’s indebtedness was comprised as follows: March 31, 2020 December 31, 2019 Revolving credit agreement $ 125,000 $ — 6.50% Notes due 2024 900,000 900,000 Debt issuance costs (10,740 ) (12,370 ) $ 1,014,260 $ 887,630 6.50% Notes On March 23, 2016 , MDC entered into an indenture (the “Indenture”) among MDC, its existing and future restricted subsidiaries that guarantee, are co-borrowers under, or grant liens to secure, the Credit Agreement, as guarantors (the “Guarantors”) and The Bank of New York Mellon, as trustee, relating to the issuance by MDC of $900,000 aggregate principal amount of the senior notes due 2024 (the “ 6.50% Notes”). The 6.50% Notes were sold in a private placement in reliance on exceptions from registration under the Securities Act of 1933. The 6.50% Notes bear interest, payable semiannually in arrears on May 1 and November 1, at a rate of 6.50% per annum. The 6.50% Notes mature on May 1, 2024 , unless earlier redeemed or repurchased. In April 2020, the Company repurchased approximately $30,000 of the 6.50% Notes. See Note 1 of the Notes to the Unaudited Condensed Consolidated Financial Statements included herein for further information. MDC may, at its option, redeem the 6.50% Notes in whole at any time or in part from time to time, at varying prices based on the timing of the redemption. If MDC experiences certain kinds of changes of control (as defined in the Indenture), holders of the 6.50% Notes may require MDC to repurchase any 6.50% Notes held by them at a price equal to 101% of the principal amount of the 6.50% Notes plus accrued and unpaid interest. In addition, if MDC sells assets under certain circumstances, it must apply the proceeds from such sale and offer to repurchase the 6.50% Notes at a price equal to 100% of the principal amount plus accrued and unpaid interest. The Indenture includes covenants that among other things, restrict MDC’s ability and the ability of its restricted subsidiaries (as defined in the Indenture) to incur or guarantee additional indebtedness; pay dividends on or redeem or repurchase the capital stock of MDC; make certain types of investments; create restrictions on the payment of dividends or other amounts from MDC’s restricted subsidiaries; sell assets; enter into transactions with affiliates; create liens; enter into sale and leaseback transactions; and consolidate or merge with or into, or sell substantially all of MDC’s assets to, another person. These covenants are subject to a number of important limitations and exceptions. The 6.50% Notes are also subject to customary events of default, including a cross-payment default and cross-acceleration provision. The Company was in compliance with all covenants at March 31, 2020 . Revolving Credit Agreement The Company is party to a $250,000 secured revolving credit facility due May 3, 2021. On March 12, 2019 (the “Amendment Effective Date”), the Company, Maxxcom Inc. (a subsidiary of the Company) (“Maxxcom”) and each of their subsidiaries party thereto entered into an Amendment to the existing senior secured revolving credit facility, dated as of May 3, 2016 (as amended, the “Credit Agreement”), among the Company, Maxxcom, each of their subsidiaries party thereto, Wells Fargo Capital Finance, LLC, as agent (“Wells Fargo”), and the lenders from time to time party thereto. Advances under the Credit Agreement are to be used for working capital and general corporate purposes, in each case pursuant to the terms of the Credit Agreement. Advances under the Credit Agreement bear interest as follows: (a)(i) LIBOR Rate Loans bear interest at the LIBOR Rate and (ii) Base Rate Loans bear interest at the Base Rate, plus (b) an applicable margin. The initial applicable margin for borrowing is 0.75% in the case of Base Rate Loans and 1.50% in the case of LIBOR Rate Loans. In addition to paying interest on outstanding principal under the Credit Agreement, MDC is required to pay an unused revolver fee to lenders under the Credit Agreement in respect of unused commitments thereunder. The Amendment provides financial covenant relief by increasing the total leverage ratio applicable on each testing date after the Amendment Effective Date through the period ending December 31, 2020 from 5.5 :1.0 to 6.25 :1.0. The total leverage ratio applicable on each testing date after December 31, 2020 will revert to 5.5 :1.0. In connection with the Amendment, the Company reduced the aggregate maximum amount of revolving commitments provided by the lenders under the Credit Agreement to $250,000 from $325,000 . The Credit Agreement, which includes financial and non-financial covenants, is guaranteed by substantially all of MDC’s present and future subsidiaries, other than immaterial subsidiaries and subject to customary exceptions and collateralized by a portion of MDC’s outstanding receivable balance. The Company is currently in compliance with all of the terms and conditions of its Credit Agreement as of March 31, 2020 . At March 31, 2020 and December 31, 2019 , the Company had issued undrawn outstanding letters of credit of $17,576 and $4,836 , respectively.

Noncontrolling and Redeemable N

Noncontrolling and Redeemable Noncontrolling Interests	3 Months Ended
	Mar. 31, 2020
Noncontrolling Interest [Abstract]
Noncontrolling and Redeemable Noncontrolling Interests	Noncontrolling and Redeemable Noncontrolling Interests When acquiring less than 100% ownership of an entity, the Company may enter into agreements that give the Company an option to purchase, or require the Company to purchase, the incremental ownership interests under certain circumstances. Where the option to purchase the incremental ownership is within the Company’s control, the amounts are recorded as noncontrolling interests in the equity section of the Company’s Unaudited Condensed Consolidated Balance Sheets . Where the incremental purchase may be required of the Company, the amounts are recorded as redeemable noncontrolling interests in mezzanine equity at their estimated acquisition date redemption value and adjusted at each reporting period for changes to their estimated redemption value through additional paid-in capital (but not less than their initial redemption value), except for foreign currency translation adjustments. On occasion, the Company may initiate a renegotiation to acquire an incremental ownership interest and the amount of consideration paid may differ materially from the amounts recorded in the Company’s Unaudited Condensed Consolidated Balance Sheets . Noncontrolling Interests Changes in amounts due to noncontrolling interest holders included in accruals and other liabilities on the Unaudited Condensed Consolidated Balance Sheets for the year ended December 31, 2019 and three months ended March 31, 2020 were as follows: Noncontrolling Balance, December 31, 2018 $ 9,278 Income attributable to noncontrolling interests 16,156 Distributions made (11,392 ) Other (1) (14 ) Balance, December 31, 2019 $ 14,028 Income attributable to noncontrolling interests 791 Distributions made (3,973 ) Other (1) (856 ) Balance, March 31, 2020 $ 9,990 (1) Other primarily consists of translation adjustments. Changes in the Company’s ownership interests in our less than 100% owned subsidiaries during the three months ended March 31, 2020 and 2019 were as follows: Three Months Ended March 31, 2020 2019 Net income (loss) attributable to MDC Partners Inc. $ 1,003 $ (113 ) Transfers from the noncontrolling interest: Increase (decrease) in MDC Partners Inc. paid-in capital for purchase of redeemable noncontrolling interests and noncontrolling interests (503 ) — Net transfers from noncontrolling interests $ (503 ) $ — Change from net income (loss) attributable to MDC Partners Inc. and transfers to noncontrolling interests $ 500 $ (113 ) Redeemable Noncontrolling Interests The following table presents changes in redeemable noncontrolling interests: Three Months Ended March 31, 2020 Year Ended December 31, 2019 Beginning Balance $ 36,973 $ 51,546 Redemptions (1,615 ) (14,530 ) Granted — — Changes in redemption value 1,218 (3,163 ) Currency translation adjustments (878 ) 3 Other (1) — 3,117 Ending Balance $ 35,698 $ 36,973 (1) Other primarily consists of the redeemable noncontrolling interest balance related to a foreign entity that was classified as held for sale as of December 31, 2018 and reclassified in 2019 . The noncontrolling shareholders’ ability to exercise any such option right is subject to the satisfaction of certain conditions, including conditions requiring notice in advance of exercise and specific employment termination conditions. In addition, these rights cannot be exercised prior to specified staggered exercise dates. The exercise of these rights at their earliest contractual date would result in obligations of the Company to fund the related amounts during 2020 to 2024. It is not determinable, at this time, if or when the owners of these rights will exercise all or a portion of these rights. The redeemable noncontrolling interest of $35,698 as of March 31, 2020 , consists of $22,494 assuming that the subsidiaries perform over the relevant future periods at their discounted cash flows earnings level and such rights are exercised, $10,931 upon termination of such owner’s employment with the applicable subsidiary or death and $2,273 representing the initial redemption value (required floor) recorded for certain acquisitions in excess of the amount the Company would have to pay should the Company acquire the remaining ownership interests for such subsidiaries. These adjustments will not impact the calculation of earnings (loss) per share if the redemption values are less than the estimated fair values. For the three months ended March 31, 2020 and 2019 , there was no related impact on the Company’s loss per share calculation.

Commitments, Contingencies and

Commitments, Contingencies and Guarantees	3 Months Ended
	Mar. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Guarantees	Commitments, Contingencies, and Guarantees Legal Proceedings. The Company’s operating entities are involved in legal proceedings of various types. While any litigation contains an element of uncertainty, the Company has no reason to believe that the outcome of such proceedings or claims will have a material adverse effect on the financial condition or results of operations of the Company. Deferred Acquisition Consideration and Options to Purchase. See Notes 5 and 8 of the Notes to the Unaudited Condensed Consolidated Financial Statements included herein for information regarding potential payments associated with deferred acquisition consideration and the acquisition of noncontrolling shareholders’ ownership interest in subsidiaries. Natural Disasters. Certain of the Company’s operations are located in regions of the United States which typically are subject to hurricanes. During the three months ended March 31, 2020 and 2019 , these operations did not incur any material costs related to damages resulting from hurricanes. Guarantees . Generally, the Company has indemnified the purchasers of certain assets in the event that a third party asserts a claim against the purchaser that relates to a liability retained by the Company. These types of indemnification guarantees typically extend for a number of years. Historically, the Company has not made any significant indemnification payments under such agreements and no amount has been accrued in the accompanying consolidated financial statements with respect to these indemnification guarantees. The Company continues to monitor the conditions that are subject to guarantees and indemnifications to identify whether it is probable that a loss has occurred and would recognize any such losses under any guarantees or indemnifications in the period when those losses are probable and estimable. Commitments. At March 31, 2020 , the Company had $17,576 of undrawn letters of credit. The Company entered into operating leases for which the commencement date has not yet occurred as of March 31, 2020. See Note 6 of the Notes to the Unaudited Condensed Consolidated Financial Statements included herein for additional information.

Share Capital

Share Capital	3 Months Ended
	Mar. 31, 2020
Share Capital [Abstract]
Share Capital	Share Capital The authorized and outstanding share capital of the Company is as follows: Series 6 Convertible Preference Shares On March 14, 2019 (the “Series 6 Issue Date”), the Company entered into a securities purchase agreement with Stagwell Agency Holdings LLC (“Stagwell Holdings”), an affiliate of Stagwell, pursuant to which Stagwell Holdings agreed to purchase (i) 14,285,714 newly authorized Class A shares (the “Stagwell Class A Shares”) for an aggregate contractual purchase price of $50,000 and (ii) 50,000 newly authorized Series 6 convertible preference shares (“Series 6 Preference Shares”) for an aggregate contractual purchase price of $50,000 . The Company received proceeds of approximately $98,620 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. The proceeds allocated to the Stagwell Class A Shares were $35,997 and to Series 6 Preference Shares were $62,623 based on their relative fair value calculated by utilizing a Monte Carlo Simulation model. In connection with the closing of the transaction, the Company increased the size of its Board and appointed two nominees designated by Stagwell Holdings. Except as required by law, the Series 6 Preference Shares do not have voting rights and are not redeemable at the option of Stagwell Holdings. The holders of the Series 6 Preference Shares have the right to convert their Series 6 Preference Shares in whole at any time and from time to time, and in part at any time and from time to time, into a number of 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 preference per share of each Series 6 Preference Share is $1,000 . The initial Conversion Price is $5.00 per Series 6 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 Series 6 Preference Shares’ liquidation preference accretes at 8.0% per annum, compounded quarterly until the five -year anniversary of the Series 6 Issue Date. During the three months ended March 31, 2020 , the Series 6 Preference Shares accreted at a monthly rate of $7.10 , for total accretion of $1,065 , bringing the aggregate liquidation preference to $54,326 as of March 31, 2020 . The accretion is considered in the calculation of net loss attributable to MDC Partners Inc. common shareholders. See Note 4 of the Notes to the Unaudited Condensed Consolidated Financial Statements included herein for further information regarding the Series 6 Preference Shares. Holders of the Series 6 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 Series 6 Preference Shares. The Series 6 Preference Shares are convertible at the Company’s option (i) on and after the two -year anniversary of the Series 6 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 Series 6 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 Series 6 Preference Shares for cash at the greater of their liquidation preference plus accrued and unpaid dividends or their as-converted value. Series 4 Convertible Preference Shares On March 7, 2017 (the “Series 4 Issue Date”), the Company issued 95,000 newly created Preference Shares (“Series 4 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 $90,123 , 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, the Company increased the size of its Board and appointed one nominee designated by the Purchaser. Except as required by law, the Series 4 Preference Shares do not have voting rights and are not redeemable at the option of the Purchaser. Subsequent to the ninetieth day following the Series 4 Issue Date, the holders of the Series 4 Preference Shares have the right to convert their Series 4 Preference Shares in whole at any time and from time to time and in part at any time and from time to time into a number of 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 preference per share of each Series 4 Preference Share is $1,000 . The Conversion Price of a Series 4 Preference Share is 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. In connection with the anti-dilution protection provision triggered by the issuance of equity securities to Stagwell Holdings, the Conversion Price per Series 4 Preference Share was reduced to $7.42 from the initial Conversion Price of $10.00 . The Series 4 Preference Shares’ liquidation preference accretes at 8.0% per annum, compounded quarterly until the five-year anniversary of the Series 4 Issue Date. During the three months ended March 31, 2020 , the Series 4 Preference Shares accreted at a monthly rate of approximately $8.33 per Series 4 Preference Share, for total accretion of $2,375 , bringing the aggregate liquidation preference to $121,126 as of March 31, 2020 . The accretion is considered in the calculation of net income (loss) attributable to MDC Partners Inc. common shareholders. See Note 4 of the Notes to the Unaudited Condensed Consolidated Financial Statements included herein for further information regarding the Series 4 Preference Shares. Holders of the Series 4 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 Series 4 Preference Shares. The Series 4 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 Series 4 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 Series 4 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 Series 4 Preference Shares for cash at the greater of their liquidation preference plus accrued and unpaid dividends or their as-converted value. Class A Common Shares (“Class A Shares”) These are an unlimited number of subordinate voting shares, carrying one vote each, with a par value of $0, entitled to dividends equal to or greater than Class B Shares, convertible at the option of the holder into one Class B Share for each Class A Share after the occurrence of certain events related to an offer to purchase all Class B shares. There were 72,479,417 and 72,150,854 Class A Shares issued and outstanding as of March 31, 2020 and December 31, 2019 , respectively. Class B Common Shares (“Class B Shares”) These are an unlimited number of voting shares, carrying twenty votes each, with a par value of $0, convertible at any time at the option of the holder into one Class A share for each Class B share. There were 3,749 and 3,749 Class B Shares issued and outstanding as of March 31, 2020 and December 31, 2019 , respectively.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements A fair value measurement assumes a transaction to sell an asset or transfer a liability occurs in the principal market for the asset or liability or, in the absence of a principal market, the most advantageous market for the asset or liability. In determining fair value, the Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible as well as considers counterparty credit risk in its assessment of fair value. The hierarchy for observable and unobservable inputs used to measure fair value into three broad levels are described below: • Level 1 - Quoted prices (unadjusted) in active markets that are accessible at the measurement date for assets or liabilities. The fair value hierarchy gives the highest priority to Level 1 inputs. • Level 2 - Observable prices that are based on inputs not quoted on active markets, but corroborated by market data. • Level 3 - Unobservable inputs are used when little or no market data is available. The fair value hierarchy gives the lowest priority to Level 3 inputs. Financial Liabilities that are not Measured at Fair Value on a Recurring Basis The following table presents certain information for our financial liability that is not measured at fair value on a recurring basis at March 31, 2020 and December 31, 2019 : March 31, 2020 December 31, 2019 Carrying Fair Value Carrying Fair Value Liabilities: 6.50% Senior Notes due 2024 $ 900,000 $ 675,000 $ 900,000 $ 812,250 Our long-term debt includes fixed rate debt. The fair value of this instrument is based on quoted market prices in markets that are not active. Therefore, this debt is classified as Level 2 within the fair value hierarchy. Financial Liabilities Measured at Fair Value on a Recurring Basis Contingent deferred acquisition consideration (Level 3 fair value measurement) is recorded at the acquisition date fair value and adjusted at each reporting period. The estimated liability is determined in accordance with various contractual valuation formulas and is dependent upon significant assumptions, such as the growth rate of the earnings of the relevant subsidiary during the contractual period and the discount rate. These growth rates are consistent with the Company's long-term forecasts. As of March 31, 2020 , the discount rate used to measure these liabilities was 9.91% . As these estimates require the use of assumptions about future performance, which are uncertain at the time of estimation, the fair value measurement presented on the Consolidated Balance Sheet is subject to material uncertainty. See Note 5 of the Notes to the Unaudited Condensed Consolidated Financial Statements included herein for additional information regarding contingent deferred acquisition consideration. At March 31, 2020 and December 31, 2019 , the carrying amount of the Company’s financial instruments, including cash and cash equivalents, accounts receivable and accounts payable, approximated fair value because of their short-term maturity. Non-financial Assets and Liabilities that are Measured at Fair Value on a Nonrecurring Basis Certain non-financial assets are measured at fair value on a nonrecurring basis, primarily goodwill, intangible assets (Level 3 fair value measurement) and right-of-use lease assets (Level 2 fair value measurement). Accordingly, these assets are not measured and adjusted to fair value on an ongoing basis but are subject to periodic evaluations for potential impairment. The Company did not recognize an impairment of goodwill or intangible assets in the three months ended March 31, 2020 and 2019. The Company recognized an impairment charge of $161 to reduce the carrying value of a right-of-use lease asset in the three months ended March 31, 2020 . See Note 6 of the Notes to the Unaudited Condensed Consolidated Financial Statements included herein for further information.

Supplemental Information

Supplemental Information	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Information	Supplemental Information Accruals and Other Liabilities At March 31, 2020 and December 31, 2019 , accruals and other liabilities included accrued media of $213,915 and $216,931 , respectively; and also included amounts due to noncontrolling interest holders for their share of profits. See Note 8 of the Notes to the Unaudited Condensed Consolidated Financial Statements included herein for additional information regarding noncontrolling interest holders’ share of profits. Goodwill and Intangible Assets Goodwill acquired as a result of business combinations which is not subject to amortization is tested for impairment annually as of October 1st of each year, or more frequently if indicators of potential impairment exist. For goodwill, impairment is assessed at the reporting unit level. Given the impact of the COVID-19 pandemic, the Company performed an interim goodwill impairment test in the first quarter of 2020. The interim test did not result in an impairment of goodwill but did result in the fair value of certain reporting units, with goodwill of approximately $230,000, exceeding their carrying value by a minimal percentage. If the duration of the COVID-19 pandemic is longer and the operational impact is greater than estimated, the Company could recognize an impairment of goodwill in the future. The Company used an income approach to measure its goodwill for impairment. This methodology incorporates the use of the discounted cash flow (“DCF”) method. The income approach requires the exercise of significant judgment and inputs, including judgment about the amount and timing of expected future cash flows, assumed terminal value and appropriate discount rates. Goodwill balances as of March 31, 2020 and December 31, 2019 , were $725,390 and $740,674 , respectively. During the first quarter of 2020 , the Company reassessed its estimate of the useful life of a trademark in the amount of $14,600 , acquired as a result of a business combination. The Company revised the useful life to 5 years from indefinite lived. Income Taxes Our tax provision for interim periods is determined using an estimated annual effective tax rate, adjusted for discrete items arising in interim periods. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”) was enacted into law and the new legislation contains several key tax provisions, including the five-year net operating loss carryback, an adjusted business interest limitation, and payroll tax deferral. The Company is required to recognize the effect of tax law changes in the period of enactment, which required the Company to reassess the net realizability of its deferred tax assets and liabilities. The Company has assessed the applicability of the CARES Act and determined there is no impact. Income tax expense for the three months ended March 31, 2020 was $13,500 (on income of $15,294 resulting in an effective tax rate of 88.3% ) compared to an expense of $748 (on income of $981 resulting in an effective tax rate of 76.2% ) for the three months ended March 31, 2019 . The income tax expense and benefit for the three months ended March 31, 2020 were impacted by capital gains, non-deductible stock compensation for which a tax benefit was not recognized, and the jurisdictional mix of earnings.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions In the ordinary course of business, the Company enters into transactions with related parties, including Stagwell and its affiliates. The transactions may range in the nature and value of services underlying the arrangements. Below are the related party transactions that are significant in nature: In October 2019, a Partner Firm of the Company entered into an arrangement with a Stagwell affiliate, in which the Stagwell affiliate and the Partner Firm will collaborate to provide various services to a client of the Partner Firm. The Partner Firm and the Stagwell affiliate pitched and won this business together, with the client ultimately determining the general scope of work for each agency. Under the arrangement, which was structured as a sub-contract due to client preference, the Partner Firm is expected to pay the Stagwell affiliate, for services provided by the Stagwell affiliate in connection with serving the client, approximately $655 which is expected to be recognized through the end of 2020. As of March 31, 2020, $565 was owed to the affiliate. In January 2020, a Partner Firm of the Company entered into an arrangement with a Stagwell affiliate to develop advertising technology for the Partner Firm. Under the arrangement the Partner Firm is expected to pay the Stagwell affiliate approximately $460 , which is expected to be recognized through May 2020. As of March 31, 2020, $170 was owed to the affiliate. On February 14, 2020, Sloane sold substantially all its assets and certain liabilities to an affiliate of Stagwell. See Note 2 of the Notes to the Consolidated Financial Statements for information related to this transaction. The Company entered into an agreement commencing on January 1, 2020 to sublease office space through July 2021 to a company whose chairman is a member of the Company’s Board of Directors. The total future rental income related to the sublease is approximately $229 .

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Segment Information	Segment Information The Company determines an operating segment if a component (i) engages in business activities from which it earns revenues and incurs expenses, (ii) has discrete financial information, and is (iii) regularly reviewed by the Chief Operating Decision Maker (“CODM”) to make decisions regarding resource allocation for the segment and assess its performance. Once operating segments are identified, the Company performs an analysis to determine if aggregation of operating segments is applicable. This determination is based upon a quantitative analysis of the expected and historic average long-term profitability for each operating segment, together with a qualitative assessment to determine if operating segments have similar operating characteristics. 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 reassessed our reportable segments to align our external reporting with how we operate the Networks under our new organizational structure. Prior periods presented have been recast to reflect the change in reportable segments. The two reportable segments that result from applying the aggregation criteria are as follows: “Integrated Agencies Network”; and “Media & Data Network.” In addition, the Company combines and discloses operating segments that do not meet the aggregation criteria as “All Other.” The Company also reports corporate expenses, as further detailed below, as “Corporate.” All segments follow the same basis of presentation and accounting policies as those described throughout the Notes to the Unaudited Condensed Consolidated Financial Statements included herein and Note 2 of the Company’s 2019 Form 10-K. • The Integrated Agencies Network reportable segment is comprised of the Company’s four integrated operating segments (Constellation, Doner Partner Network, Anomaly Alliance, and Colle McVoy). These operating segments share similar characteristics related to (i) the nature of their services; (ii) the type of clients and the methods used to provide services; and (iii) the extent to which they may be impacted by global economic and geopolitical risks. In addition, these operating segments compete with each other for new business and from time to time have business move between them. The Company believes the historic and expected average long-term profitability is similar among the operating segments aggregated in the Integrated Agencies Network reportable segment. The operating segments within the Integrated Agencies Network reportable segment provide a range of different services for its clients, primarily including strategy, creative and production for advertising campaigns across a variety of platforms (print, digital, social media, television broadcast), public relations and communications services, experiential, social media and influencer marketing. • The Media & Data Network reportable segment is comprised of a single operating segment that combines media buying and planning across a range of platforms (out-of-home, paid search, social media, lead generation, programmatic, television broadcast) with technology and data capabilities. • All Other consists of the Company’s remaining operating segments that provide a range of services including advertising, public relations and marketing communication services, but generally do not have similar services offerings or financial characteristics as those aggregated in the reportable segments. The All Other category includes Allison & Partners, Bruce Mau, Forsman & Bodenfors, Hello, Team and Vitro. • Corporate consists of corporate office expenses incurred in connection with the strategic resources provided to the operating segments, as well as certain other centrally managed expenses that are not fully allocated to the operating segments. These office and general expenses include (i) salaries and related expenses for corporate office employees, including employees dedicated to supporting the operating segments, (ii) occupancy expenses relating to properties occupied by all corporate office employees, (iii) other office and general expenses including professional fees for the financial statement audits and other public company costs, and (iv) certain other professional fees managed by the corporate office. Additional expenses managed by the corporate office that are directly related to the operating segments are allocated to the appropriate reportable segment and the All Other category. Three Months Ended March 31, 2020 2019 Revenue: Integrated Agencies Network $ 208,328 $ 206,910 Media & Data Network 41,058 43,232 All Other 78,356 78,649 Total $ 327,742 $ 328,791 Segment operating income (loss): Integrated Agencies Network $ 29,193 $ 15,512 Media & Data Network 617 (1,649 ) All Other 7,857 6,641 Corporate (8,338 ) (4,822 ) Total $ 29,329 $ 15,682 Other Income (Expenses): Interest expense and finance charges, net $ (15,612 ) $ (16,760 ) Foreign exchange gain (loss) (14,757 ) 5,442 Other, net 16,334 (3,383 ) Income before income taxes and equity in earnings of non-consolidated affiliates 15,294 981 Income tax expense 13,500 748 Income before equity in earnings of non-consolidated affiliates 1,794 233 Equity in earnings of non-consolidated affiliates — 83 Net income 1,794 316 Net income attributable to the noncontrolling interest (791 ) (429 ) Net income (loss) attributable to MDC Partners Inc. $ 1,003 $ (113 ) Three Months Ended March 31, 2020 2019 Depreciation and amortization: Integrated Agencies Network $ 6,267 $ 5,715 Media & Data Network 808 993 All Other 1,899 1,913 Corporate 232 217 Total $ 9,206 $ 8,838 Stock-based compensation: Integrated Agencies Network $ 2,861 $ 4,459 Media & Data Network (13 ) — All Other 80 86 Corporate 142 (1,573 ) Total $ 3,070 $ 2,972 Capital expenditures: Integrated Agencies Network $ 835 $ 3,049 Media & Data Network 86 138 All Other 323 418 Corporate 302 1 Total $ 1,546 $ 3,606 The Company’s CODM does not use segment assets to allocate resources or to assess performance of the segments and therefore, total segment assets have not been disclosed. See Note 3 of the Notes to the Unaudited Condensed Consolidated Financial Statements included herein for a summary of the Company’s revenue by geographic region for three months ended March 31, 2020 and 2019 .

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
By Location
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue		The following table presents revenue disaggregated by geography for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, Geographic Location Reportable Segment 2020 2019 United States All $ 264,561 $ 263,017 Canada All 18,256 22,378 Other All 44,925 43,396 $ 327,742 $ 328,791
Industry Vertical
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	The following table presents revenue disaggregated by client industry vertical for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, Industry Reportable Segment 2020 2019 Food & Beverage All $ 58,091 $ 66,663 Retail All 36,303 32,580 Consumer Products All 39,769 35,001 Communications All 41,045 39,798 Automotive All 25,192 18,191 Technology All 25,535 26,616 Healthcare All 24,066 23,297 Financials All 24,005 25,126 Transportation and Travel/Lodging All 20,486 17,441 Other All 33,250 44,078 $ 327,742 $ 328,791

Income (Loss) Per Common Share

Income (Loss) Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Schedule of Calculation of Numerator and Denominator in Earnings Per Share	The following table sets forth the computation of basic and diluted income (loss) per common share: Three Months Ended March 31, 2020 2019 Numerator: Net income (loss) attributable to MDC Partners Inc. $ 1,003 $ (113 ) Accretion on convertible preference shares (3,440 ) (2,383 ) Net loss attributable to MDC Partners Inc. common shareholders $ (2,437 ) $ (2,496 ) Denominator: Basic weighted average number of common shares outstanding 72,397,661 60,258,102 Diluted weighted average number of common shares outstanding 72,397,661 60,258,102 Basic $ (0.03 ) $ (0.04 ) Diluted $ (0.03 ) $ (0.04 )

Deferred Acquisition Consider_2

Deferred Acquisition Consideration (Tables)	3 Months Ended
	Mar. 31, 2020
Business Combinations [Abstract]
Schedule of Changes in Contingent Deferred Acquisition Consideration	The following table presents changes in contingent deferred acquisition consideration, which is measured at fair value on a recurring basis using significant unobservable inputs, and a reconciliation to the amounts reported on the balance sheets as of March 31, 2020 and December 31, 2019 . March 31, December 31, 2020 2019 Beginning Balance of contingent payments $ 74,671 $ 82,598 Payments (1,125 ) (30,719 ) Redemption value adjustments (1) (2,575 ) 15,451 Additions - acquisitions and step-up transactions 1,389 7,145 Other (2) (185 ) 196 Ending Balance of contingent payments $ 72,175 $ 74,671 Fixed payments 561 549 $ 72,736 $ 75,220 (1) Redemption value adjustments are fair value changes from the Company’s initial estimates of deferred acquisition payments and stock-based compensation charges relating to acquisition payments that are tied to continued employment. Redemption value adjustments are recorded within cost of services sold and office and general expenses on the Unaudited Condensed Consolidated Statement of Operations . (2) Other primarily consists of translation adjustments. The following table presents the impact to the Company’s statement of operations due to the redemption value adjustments for the contingent deferred acquisition consideration: Three Months Ended March 31, 2020 2019 Income attributable to fair value adjustments $ (4,600 ) $ (7,643 ) Stock-based compensation 2,025 809 Redemption value adjustments $ (2,575 ) $ (6,834 )

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Lease Costs and Other Quantitative Information	The following table presents lease costs and other quantitative information for the three months ended March 31, 2020 and 2019 : Three Months Ended March 31, 2020 2019 Lease Cost: Operating lease cost $ 16,391 $ 16,441 Variable lease cost 4,655 4,964 Sublease rental income (2,805 ) (1,599 ) Total lease cost $ 18,241 $ 19,806 Additional information: Cash paid for amounts included in the measurement of lease liabilities for operating leases Operating cash flows $ 17,635 $ 15,652 Right-of-use assets obtained in exchange for operating lease liabilities $ 7,119 $ 256,818 Weighted average remaining lease term (in years) - Operating leases 7.0 7.3 Weighted average discount rate - Operating leases 8.7 8.7
Minimum Future Rental Payments	The following table presents minimum future rental payments under the Company’s leases at March 31, 2020 and their reconciliation to the corresponding lease liabilities: Maturity Analysis Remaining 2020 $ 52,025 2021 59,901 2022 49,774 2023 44,573 2024 38,111 Thereafter 103,505 Total 347,889 Less: Present value discount (88,613 ) Lease liability $ 259,276

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Schedule of Debt	March 31, 2020 December 31, 2019 Revolving credit agreement $ 125,000 $ — 6.50% Notes due 2024 900,000 900,000 Debt issuance costs (10,740 ) (12,370 ) $ 1,014,260 $ 887,630

Noncontrolling and Redeemable_2

Noncontrolling and Redeemable Noncontrolling Interests (Tables)	3 Months Ended
	Mar. 31, 2020
Noncontrolling Interest [Abstract]
Change In Noncontrolling Interest [Table Text Block]	Changes in amounts due to noncontrolling interest holders included in accruals and other liabilities on the Unaudited Condensed Consolidated Balance Sheets for the year ended December 31, 2019 and three months ended March 31, 2020 were as follows: Noncontrolling Balance, December 31, 2018 $ 9,278 Income attributable to noncontrolling interests 16,156 Distributions made (11,392 ) Other (1) (14 ) Balance, December 31, 2019 $ 14,028 Income attributable to noncontrolling interests 791 Distributions made (3,973 ) Other (1) (856 ) Balance, March 31, 2020 $ 9,990
Noncontrolling Interest [Table Text Block]	Changes in the Company’s ownership interests in our less than 100% owned subsidiaries during the three months ended March 31, 2020 and 2019 were as follows: Three Months Ended March 31, 2020 2019 Net income (loss) attributable to MDC Partners Inc. $ 1,003 $ (113 ) Transfers from the noncontrolling interest: Increase (decrease) in MDC Partners Inc. paid-in capital for purchase of redeemable noncontrolling interests and noncontrolling interests (503 ) — Net transfers from noncontrolling interests $ (503 ) $ — Change from net income (loss) attributable to MDC Partners Inc. and transfers to noncontrolling interests $ 500 $ (113 )
Redeemable Noncontrolling Interest [Table Text Block]	The following table presents changes in redeemable noncontrolling interests: Three Months Ended March 31, 2020 Year Ended December 31, 2019 Beginning Balance $ 36,973 $ 51,546 Redemptions (1,615 ) (14,530 ) Granted — — Changes in redemption value 1,218 (3,163 ) Currency translation adjustments (878 ) 3 Other (1) — 3,117 Ending Balance $ 35,698 $ 36,973 (1) Other primarily consists of the redeemable noncontrolling interest balance related to a foreign entity that was classified as held for sale as of December 31, 2018 and reclassified in 2019 .

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value of Financial Liability Measured on a Non-recurring Basis	The following table presents certain information for our financial liability that is not measured at fair value on a recurring basis at March 31, 2020 and December 31, 2019 : March 31, 2020 December 31, 2019 Carrying Fair Value Carrying Fair Value Liabilities: 6.50% Senior Notes due 2024 $ 900,000 $ 675,000 $ 900,000 $ 812,250

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Three Months Ended March 31, 2020 2019 Revenue: Integrated Agencies Network $ 208,328 $ 206,910 Media & Data Network 41,058 43,232 All Other 78,356 78,649 Total $ 327,742 $ 328,791 Segment operating income (loss): Integrated Agencies Network $ 29,193 $ 15,512 Media & Data Network 617 (1,649 ) All Other 7,857 6,641 Corporate (8,338 ) (4,822 ) Total $ 29,329 $ 15,682 Other Income (Expenses): Interest expense and finance charges, net $ (15,612 ) $ (16,760 ) Foreign exchange gain (loss) (14,757 ) 5,442 Other, net 16,334 (3,383 ) Income before income taxes and equity in earnings of non-consolidated affiliates 15,294 981 Income tax expense 13,500 748 Income before equity in earnings of non-consolidated affiliates 1,794 233 Equity in earnings of non-consolidated affiliates — 83 Net income 1,794 316 Net income attributable to the noncontrolling interest (791 ) (429 ) Net income (loss) attributable to MDC Partners Inc. $ 1,003 $ (113 ) Three Months Ended March 31, 2020 2019 Depreciation and amortization: Integrated Agencies Network $ 6,267 $ 5,715 Media & Data Network 808 993 All Other 1,899 1,913 Corporate 232 217 Total $ 9,206 $ 8,838 Stock-based compensation: Integrated Agencies Network $ 2,861 $ 4,459 Media & Data Network (13 ) — All Other 80 86 Corporate 142 (1,573 ) Total $ 3,070 $ 2,972 Capital expenditures: Integrated Agencies Network $ 835 $ 3,049 Media & Data Network 86 138 All Other 323 418 Corporate 302 1 Total $ 1,546 $ 3,606

Basis of Presentation and Rec_2

Basis of Presentation and Recent Developments (Details) - 6.50% Notes due 2024 - Senior Notes - USD ($)	1 Months Ended
	Apr. 30, 2020	Mar. 31, 2019	Mar. 23, 2016
Debt [Line Items]
Aggregate principal amount			$ 900,000,000
Interest rate, stated percentage		6.50%	6.50%
Subsequent Event [Member]
Debt [Line Items]
Debt Acquired	$ 30,000,000
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed	74.00%
Long-term Debt	$ 22,000,000
Long-term Debt, Accrued Interest	1,000,000
Gain (Loss) on Extinguishment of Debt	$ 8,000,000

Acquisitions and Dispositions (

Acquisitions and Dispositions (Details Textual) - USD ($) $ in Thousands	Mar. 19, 2020	Feb. 14, 2020	Nov. 15, 2019	Apr. 01, 2019	Mar. 08, 2019	Mar. 31, 2020	Dec. 31, 2018	Dec. 31, 2019
Business Acquisition [Line Items]
Deferred acquisition consideration						$ 72,736		$ 75,220
Redeemable noncontrolling interest, redemptions, value						1,615	$ 14,530
KWT Global [Member]
Business Acquisition [Line Items]
Remaining ownership interest acquired (percent)	22.50%
Aggregate purchase price	$ 2,118
Closing cash payment	729
Deferred acquisition consideration	1,389
Redeemable noncontrolling interest, redemptions, value						$ 1,615
Reduction in noncontrolling interests	$ 503
Laird - Partners [Member]
Business Acquisition [Line Items]
Remaining ownership interest acquired (percent)			35.00%
Aggregate purchase price			$ 2,389
Closing cash payment			1,588
Deferred acquisition consideration			801
Business acquisitions and step-up transactions, net of tax			(5,045)
Reduction in noncontrolling interests			$ 2,656
Hunter PR LLC [Member]
Business Acquisition [Line Items]
Remaining ownership interest acquired (percent)				35.00%
Aggregate purchase price				$ 10,234
Closing cash payment				3,890
Deferred acquisition consideration				6,344
Business acquisitions and step-up transactions, net of tax				(9,486)
Reduction in noncontrolling interests				$ 745
Sloane and Company LLC [Member]
Business Acquisition [Line Items]
Proceeds from Divestiture of Businesses		$ 26,000
Gain (loss) on disposition of business		$ 16,131
Kingsdale Partners LP [Member]
Business Acquisition [Line Items]
Proceeds from Divestiture of Businesses					$ 50,000
Gain (loss) on disposition of business					$ 3,000

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Services	$ 327,742	$ 328,791
United States
Disaggregation of Revenue [Line Items]
Services	264,561	263,017
Canada
Disaggregation of Revenue [Line Items]
Services	18,256	22,378
Other
Disaggregation of Revenue [Line Items]
Services	44,925	43,396
Food & Beverage
Disaggregation of Revenue [Line Items]
Services	58,091	66,663
Retail
Disaggregation of Revenue [Line Items]
Services	36,303	32,580
Consumer Products
Disaggregation of Revenue [Line Items]
Services	39,769	35,001
Communications
Disaggregation of Revenue [Line Items]
Services	41,045	39,798
Automotive
Disaggregation of Revenue [Line Items]
Services	25,192	18,191
Technology
Disaggregation of Revenue [Line Items]
Services	25,535	26,616
Healthcare
Disaggregation of Revenue [Line Items]
Services	24,066	23,297
Financials
Disaggregation of Revenue [Line Items]
Services	24,005	25,126
Transportation and Travel/Lodging
Disaggregation of Revenue [Line Items]
Services	20,486	17,441
Other
Disaggregation of Revenue [Line Items]
Services	$ 33,250	$ 44,078

Revenue - Contract Assets and L

Revenue - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2020	Jun. 30, 2019	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Unbilled service fees	$ 76,753		$ 66,119
Unbilled outside vendor costs, billable to clients	22,763		30,133
Advance billings	146,803		$ 171,742
Decrease in advance billings	(24,939)
Revenue recognized		$ 104,937
Remaining performance obligation, amount	$ 35,771
Remaining performance obligation, current year, percentage	87.00%
Remaining performance obligation, year two, percentage	11.00%
Remaining performance obligation, year three, percentage	2.00%

Income (Loss) Per Common Shar_2

Income (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Class of Stock [Line Items]
Net loss attributable to MDC Partners Inc.	$ 1,003	$ (113)
Numerator
Net loss attributable to MDC Partners Inc. common shareholders	(2,437)	(2,496)
Net loss attributable to MDC Partners Inc. common shareholders	$ (2,437)	$ (2,496)
Denominator
Denominator for basic income (loss) per common share - weighted average common shares	72,397,661	60,258,102
Denominator for diluted income (loss) per common share - adjusted weighted shares and assumed conversions	72,397,661	60,258,102
Earnings per share, basic	$ (0.03)	$ (0.04)
Earnings per share, diluted	$ (0.03)	$ (0.04)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,835,770,000
MDC Partners Inc. Shareholders' Deficit
Class of Stock [Line Items]
Net loss attributable to MDC Partners Inc.	$ 1,003	$ (113)
Series 4 Convertible Preferred Stock | Convertible Preferred Stock
Numerator
Accretion on and net income allocated to convertible preference shares	3,440	$ 2,383
Denominator
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		1,633,464,000
Series 4 Convertible Preferred Stock [Domain] | Convertible Preferred Stock
Numerator
Accretion on and net income allocated to convertible preference shares	$ (3,440)	$ (2,383)

Income (Loss) Per Common Shar_3

Income (Loss) Per Common Share (Details Textual) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)	2,835,770,000
Contingent Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)	2,203,717	257,280
Series 4 Convertible Preferred Stock | Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)		1,633,464,000
Shares outstanding (shares)	145,000,000	145,000,000	145,000,000	95,000,000
Convertible preferred stock, common shares issuable upon conversion (shares)	27,189,411		25,118,813

Deferred Acquisition Consider_3

Deferred Acquisition Consideration (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance of contingent payments	$ 74,671	$ 82,598	$ 82,598
Payments	1,125		30,719
Redemption value adjustments	(2,575)	(6,834)	15,451
Additions	1,389		7,145
Foreign translation adjustment	(185)		196
Ending balance of contingent payments	72,175		74,671
Deferred acquisition consideration	72,736		75,220
Stock-based compensation	2,025	809
Fixed payments
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Deferred acquisition consideration	561		$ 549
Contingent Payment
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Income attributable to fair value adjustments	$ (4,600)	$ (7,643)

Leases - Additional Information

Leases - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Jun. 30, 2019
Leases [Abstract]
Lease payments	$ 112,000,000,000
Leases not yet commenced, liability		$ 124,233,000,000
Impairment of right-of-use asset	$ 200,000

Leases - Lease Costs and Other

Leases - Lease Costs and Other Quantitative Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Leases [Abstract]
Operating lease cost	$ 16,391	$ 16,441
Variable lease cost	4,655	4,964
Sublease rental income	(2,805)	(1,599)
Total lease cost	18,241	19,806
Operating cash flows	17,635	15,652
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 7,119	$ 256,818
Weighted average remaining lease term (in years) - Operating leases	7 years 18 days	7 years 3 months 19 days
Weighted average discount rate - Operating leases	870.00%	870.00%

Leases - Minimum Future Rental

Leases - Minimum Future Rental Payments (Details) $ in Thousands	Mar. 31, 2020USD ($)
Leases [Abstract]
Remaining 2019	$ 52,025
2020	59,901
2021	49,774
2022	44,573
2023	38,111
Thereafter	103,505
Total	347,889
Less: Present value discount	(88,613)
Lease liability	$ 259,276

Debt (Details)

Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt [Line Items]
Revolving credit agreement	$ 125,000	$ 0
Debt issuance costs	(10,740)	(12,370)
Debt, Long-term and Short-term, Combined Amount, Total	1,014,260	887,630
6.50% Notes due 2024
Debt [Line Items]
Senior Notes	$ 900,000	$ 900,000

Debt (Details Textual)

Debt (Details Textual)	May 01, 2024	Mar. 23, 2016USD ($)	Apr. 30, 2020USD ($)	Dec. 31, 2020	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Mar. 31, 2019	Mar. 12, 2019USD ($)	May 03, 2016USD ($)
Debt [Line Items]
Amount outstanding under the line of credit					$ 125,000,000	$ 0
Amount of letters of credit outstanding					$ 17,576,000	$ 4,836,000
Wells Fargo Capital Finance, LLC | Base Rate
Debt [Line Items]
Interest rate, stated percentage									1.50%
Wells Fargo Capital Finance, LLC | Non-Prime Rate and Prime Rate on European Advances
Debt [Line Items]
Interest rate, stated percentage									0.75%
Wells Fargo Capital Finance, LLC | Revolving Credit Facility [Member]
Debt [Line Items]
Maximum borrowing capacity									$ 325,000,000
Ratio of Indebtedness to Net Capital									5.5
Senior Notes | 6.50% Notes due 2024
Debt [Line Items]
Aggregate principal amount		$ 900,000,000
Interest rate, stated percentage		6.50%					6.50%
Percentage of redemption price, redemption date, latest for redemption at face amounttion Price, Redemption Date, Latest For Redemption At Face Amount		100.00%
Percentage of redemption price, change in ownership controllatest for redemption at face amount		101.00%
Debt instrument, maturity date		May 1, 2024
Line of Credit [Member] | Amendment, Credit Agreement [Member]
Debt [Line Items]
Maximum borrowing capacity								$ 250,000,000
Ratio of Indebtedness to Net Capital								6.25
Forecast | Wells Fargo Capital Finance, LLC | 6.50% Notes due 2024
Debt [Line Items]
Debt instrument, maturity date	May 1, 2024
Forecast | Line of Credit [Member] | Amendment, Credit Agreement [Member]
Debt [Line Items]
Ratio of Indebtedness to Net Capital				5.5
Subsequent Event [Member] | Senior Notes | 6.50% Notes due 2024
Debt [Line Items]
Debt Acquired			$ 30,000,000

Noncontrolling and Redeemable_3

Noncontrolling and Redeemable Noncontrolling Interests (Details Textual) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Noncontrolling Interest [Line Items]
Redeemable Noncontrolling Interest, Equity, Fair Value	$ 35,698	$ 36,973	$ 51,546
Vesting over period [Member]
Noncontrolling Interest [Line Items]
Redeemable Noncontrolling Interest, Equity, Fair Value	22,494
Termination, disability, or death [Member]
Noncontrolling Interest [Line Items]
Redeemable Noncontrolling Interest, Equity, Fair Value	10,931
Acquisition Value in excess of Redemption Value [Member]
Noncontrolling Interest [Line Items]
Redeemable Noncontrolling Interest, Equity, Fair Value	$ 2,273
MDC PARTNERS [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interest, ownership percentage by Parent (percent)	100.00%

Noncontrolling and Redeemable_4

Noncontrolling and Redeemable Noncontrolling Interests - Changes in Amounts Due to Noncontrolling Interest (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Noncontrolling Interest [Abstract]
Beginning balance	$ 14,028	$ 9,278	$ 9,278
Income attributable to noncontrolling interests	791	$ 429	16,156
Distributions made	(3,973)		(11,392)
Other	(856)		(14)
Ending balance	$ 9,990		$ 14,028

Noncontrolling and Redeemable_5

Noncontrolling and Redeemable Noncontrolling Interests - Changes in Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Noncontrolling Interest [Line Items]
Net loss attributable to MDC Partners Inc.	$ 1,003	$ (113)
Increase (decrease) in MDC Partners Inc. paid-in capital for purchase of redeemable noncontrolling interests and noncontrolling interests	(503)	0
Change from net income (loss) attributable to MDC Partners Inc. and transfers to noncontrolling interests	(500)	113
MDC Partners Inc. Shareholders' Deficit
Noncontrolling Interest [Line Items]
Net loss attributable to MDC Partners Inc.	1,003	(113)
Increase (decrease) in MDC Partners Inc. paid-in capital for purchase of redeemable noncontrolling interests and noncontrolling interests	$ (503)	$ 0

Noncontrolling and Redeemable_6

Noncontrolling and Redeemable Noncontrolling Interests - Changes in Redeemable Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2018
Noncontrolling Interest [Abstract]
Beginning Balance	$ 36,973
Redemptions	(1,615)	$ (14,530)
Granted	0	0
Changes in redemption value	1,218	(3,163)
Currency translation adjustments	(878)	3
Other	0	3,117
Ending Balance	$ 35,698	$ 51,546

Commitments, Contingencies an_2

Commitments, Contingencies and Guarantees (Details Textual) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Amount of letters of credit outstanding	$ 17,576	$ 4,836

Share Capital (Details Textual)

Share Capital (Details Textual)	Mar. 14, 2019USD ($)$ / sharesshares	Mar. 07, 2017USD ($)$ / shares	Mar. 31, 2020USD ($)vote$ / sharesshares	Mar. 31, 2019USD ($)shares	Dec. 31, 2019USD ($)shares	Dec. 31, 2018USD ($)shares
Share Capital [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest			$ (172,757,000)	$ (174,273,000)	$ (179,389,000)	$ (246,967,000)
Issuance of common and convertible preference shares				97,629,000
Series 4 Convertible Preferred Stock
Share Capital [Line Items]
Proceeds from issuance of common and convertible preference shares, net of issuance costs			0	97,629,000
Preferred Stock
Share Capital [Line Items]
Proceeds from issuance of common and convertible preference shares, net of issuance costs	$ 98,620,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest		$ 90,123,000	152,746,000	152,117,000	$ 152,746,000	$ 90,123,000
Issuance of common and convertible preference shares				$ 61,994,000
Preferred Stock | Series 4 Convertible Preferred Stock
Share Capital [Line Items]
Proceeds from issuance of common and convertible preference shares, net of issuance costs		$ 95,000
Preferred Stock, Liquidation Preference Per Share | $ / shares		$ 1,000
Preferred Stock, Conversion Price Per Preference Share | $ / shares	$ 7.42	$ 10
Preferred Stock, Accretion of Redemption Discount			2,000
Preferred Stock, Liquidation Preference, Value			$ 121,000
Shares outstanding (shares) | shares			145,000,000	145,000,000	145,000,000	95,000,000
Preferred Stock, Conversion Basis, Common Stock Class A Closing Trade Price		125.00%
Preferred Stock, Liquidation Preference Percentage Rate, Change of Control of the Company		7.00%
Preferred Stock | Series 6 Convertible Preferred Stock
Share Capital [Line Items]
Stock Issued During Period, Shares, Issued For Services, Convertible Preferred Shares | shares	50,000
Proceeds from issuance of common and convertible preference shares, net of issuance costs	$ 50,000,000
Preferred Stock, Liquidation Preference Per Share | $ / shares	$ 1,000
Preferred Stock, Conversion Price Per Preference Share | $ / shares	$ 5
Preferred Stock, Accretion Percentage, Preference	8.00%	8.00%
Preferred Stock, Accretion Rate, Preference Per Share | $ / shares			$ 8.33
Preferred Stock, Convertible Preference Shares, Accretion Period	5 years
Preferred Stock, Monthly Accretion of Redemption Discount			$ 7.10
Preferred Stock, Accretion of Redemption Discount			1,000
Preferred Stock, Liquidation Preference, Value			54,000
Preferred Stock, Convertible Preference Shares, Convertible at Company's Option, Term	2 years
Preferred Stock, Conversion Basis, Common Stock Class A Closing Trade Price	125.00%
Preferred Stock, Dividend Rate, Percentage	7.00%
Additional Paid-in Capital
Share Capital [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest			$ 99,587,000	$ 98,693,000	$ 101,469,000	$ 58,579,000
Issuance of common and convertible preference shares	$ 35,997			$ 35,635,000
Common Stock | Common Class A
Share Capital [Line Items]
Stock Issued During Period, Shares, Issued for Services | shares	14,285,714
Proceeds from Issuance of Common Stock	$ 50,000,000
Shares outstanding (shares) | shares			72,479,417		72,150,854
Common stock, voting rights, number of votes per share | vote			1
Common Stock | Common Class B
Share Capital [Line Items]
Shares outstanding (shares) | shares			3,749		3,749
Common stock, voting rights, number of votes per share | vote			20
Contingent Consideration, Liability Settlements [Domain] | Preferred Stock | Series 4 Convertible Preferred Stock
Share Capital [Line Items]
Issuance of common and convertible preference shares	$ 62,623

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Liabilities:
Discount rate	9.91%
Impairment of right-of-use asset	$ 200
6.50% Notes due 2024 | Fair Value, Inputs, Level 1 | Senior Notes
Liabilities:
Long term debt, Carrying Amount	900,000	$ 900,000
Long term debt, Fair Value	$ 675,000	$ 812,250

Supplemental Information (Detai

Supplemental Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued media	$ 213,915,000		$ 216,931,000
Goodwill	725,390,000		$ 740,674,000
Indefinite-lived intangible assets acquired	$ 14,600
Finite-lived intangible assets, remaining amortization period	5 years
Income tax expense	$ 13,500,000	$ 748,000
Income (loss) before income taxes and equity in earnings of non-consolidated affiliates	$ 15,294,000	$ 981,000
Effective tax rate (percent)	76.20%	88.26991%

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	Jan. 01, 2020	Mar. 31, 2020	Mar. 31, 2019
Related Party Transaction [Line Items]
Sublease rental income		$ 2,805	$ 1,599
Stagwell Subsidiary [Member] | Services Provided By Subisidiary [Member]
Related Party Transaction [Line Items]
Due to Related Parties		655
Accounts Payable, Related Parties		565
Stagwell Subsidiary [Member] | Development of Advertising Technology [Member]
Related Party Transaction [Line Items]
Due to Related Parties		460
Accounts Payable, Related Parties		$ 170
Other Company [Member] | Board of Directors Chairman [Member]
Related Party Transaction [Line Items]
Sublease rental income	$ 229

Segment Information (Details 1)

Segment Information (Details 1) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020USD ($)operating_segmentreportable_segment	Mar. 31, 2019USD ($)	Dec. 31, 2019USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | reportable_segment	2
Number of operating segments | operating_segment	4
Revenue	$ 327,742	$ 328,791
Segment operating income (loss)	29,329	15,682
Interest expense and finance charges	(15,612)	(16,760)
Foreign exchange gain (loss)	(14,757)	5,442
Other, net	16,334	(3,383)
Income (loss) before income taxes and equity in earnings of non-consolidated affiliates	15,294	981
Income tax expense	13,500	748
Income before equity in earnings of non-consolidated affiliates	1,794	233
Equity in earnings of non-consolidated affiliates	0	83
Net income	1,794	316
Net income attributable to the noncontrolling interest	(791)	(429)	$ (16,156)
Net income (loss) attributable to MDC Partners Inc.	1,003	(113)
Depreciation and amortization	9,206	8,838
Stock-based compensation	3,070	2,972
Capital expenditures	1,546	3,606
Global Integrated Agencies
Segment Reporting Information [Line Items]
Revenue	208,328	206,910
Segment operating income (loss)	29,193	15,512
Depreciation and amortization	6,267	5,715
Stock-based compensation	2,861	4,459
Capital expenditures	835	3,049
Media Services
Segment Reporting Information [Line Items]
Revenue	41,058	43,232
Segment operating income (loss)	617	(1,649)
Depreciation and amortization	808	993
Stock-based compensation	(13)	0
Capital expenditures	86	138
All Other
Segment Reporting Information [Line Items]
Revenue	78,356	78,649
Segment operating income (loss)	7,857	6,641
Depreciation and amortization	1,899	1,913
Stock-based compensation	80	86
Capital expenditures	323	418
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Segment operating income (loss)	(8,338)	(4,822)
Depreciation and amortization	232	217
Stock-based compensation	142	(1,573)
Capital expenditures	$ 302	$ 1