Segment Information (Details 1) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) reportable_segment	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | reportable_segment			3
Revenues	$ 259,678	$ 362,130	$ 587,420	$ 690,921	$ 1,415,803	$ 1,475,088	$ 1,513,779
Segment operating income (loss)	98	23,442	29,427	39,123
EBITDA	36,161	46,437	75,729	67,911
Interest expense and finance charges	(15,941)	(16,413)	(31,553)	(33,174)
Foreign exchange gain (loss)	5,342	2,932	(9,415)	8,374
Other, net	5,884	(746)	22,218	(4,128)
Income (loss) before income taxes and equity in earnings of non-consolidated affiliates	(4,617)	9,215	10,677	10,195	20,867	(88,669)	86,022
Income tax expense (benefit)	(7,923)	2,088	5,577	2,835	10,316	29,615	(168,358)
Income before equity in earnings (losses) of non-consolidated affiliates	3,306	7,127	5,100	7,360
Equity in earnings (losses) of non-consolidated affiliates	(798)	206	(798)	289
Net income (loss)	2,508	7,333	4,302	7,649
Net income attributable to the noncontrolling interest	(3,101)	(3,043)	(3,892)	(3,472)	(16,156)
Net income (loss) attributable to MDC Partners Inc.	(593)	4,290	410	4,177
Depreciation and amortization	(8,899)	(10,663)	(18,105)	(19,501)
Asset Impairment Charges	(18,839)	0	(19,000)	0	(8,599)	(87,204)	(5,471)
Depreciation, Depletion and Amortization, Nonproduction	8,899	10,663		19,501
Depreciation			18,105	19,501
Stock-based compensation	(1,039)	(3,634)	(4,109)	(6,606)
Change in contingent purchase price obligation	(2,312)	(2,073)	2,288	5,570
Proceeds from (Payments to) Noncontrolling Interests	(1,079)	(31)	(1,065)	(31)
Capital expenditures	2,144	4,317	3,690	7,923
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	(4,102)	775	(6,539)	(1,448)	$ (17,557)	$ (138,362)	$ 204,832
Global Integrated Agencies, Group A
Segment Reporting Information [Line Items]
Revenues	82,735	103,248	173,356	176,987
EBITDA	17,205	18,241	33,507	19,156
Depreciation and amortization	(1,566)	(2,348)	(3,307)	(4,289)
Stock-based compensation	105	(639)	(1,856)	(4,234)
Capital expenditures	208	2,157	566	4,038
Global Integrated Agencies, Group B
Segment Reporting Information [Line Items]
Revenues	93,398	133,394	211,105	266,565
EBITDA	16,387	24,848	33,523	43,128
Depreciation and amortization	(4,387)	(4,318)	(8,913)	(8,092)
Stock-based compensation	(746)	(1,627)	(1,646)	(2,491)
Capital expenditures	(272)	1,013	205	2,181
Media Services
Segment Reporting Information [Line Items]
Revenues	28,551	39,456	69,609	82,688
EBITDA	892	1,004	2,679	1,036
Depreciation and amortization	(807)	(1,335)	(1,615)	(2,328)
Stock-based compensation	(4)	(6)	9	(6)
Capital expenditures	111	206	197	344
All Other
Segment Reporting Information [Line Items]
Revenues	54,994	86,032	133,350	164,681
EBITDA	6,885	10,937	16,790	17,737
Depreciation and amortization	(1,903)	(2,441)	(3,802)	(4,354)
Stock-based compensation	(118)	(170)	(198)	(256)
Capital expenditures	134	923	457	1,341
Corporate, Non-Segment
Segment Reporting Information [Line Items]
EBITDA	(5,208)	(8,593)	(10,770)	(13,146)
Depreciation and amortization	(236)	(221)	(468)	(438)
Stock-based compensation	(276)	(1,192)	(418)	381
Capital expenditures	$ 1,963	$ 18	$ 2,265	$ 19