Segment Information (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) segment	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment			1
Revenue	$ 349,254	$ 328,415	$ 995,343	$ 967,243
Cost of services sold	235,659	212,925	675,940	648,386
Office and general expenses	83,303	78,786	233,840	206,169
Depreciation and amortization	11,412	13,086	34,068	39,393
Goodwill, Impairment Loss	29,631	0	29,631	0
Operating profit	(10,751)	23,618	21,864	73,295
Other Income (Expense):
Other income, net	(6,008)	(15,623)	9,530	(29,315)
Interest expense, net	(16,322)	(14,524)	(48,690)	(42,684)
Loss On Redemption Of Notes	0	0	(33,298)	0
Loss from continuing operations before income taxes, equity in affiliates	(33,081)	(6,529)	(50,594)	1,296
Income tax benefit	(540)	(1,191)	1,893	(566)
Loss from continuing operations before equity in affiliates	(32,541)	(5,338)	(52,487)	1,862
Equity in earnings of non-consolidated affiliates	70	172	9	627
Income from continuing operations	(32,471)	(5,166)	(52,478)	2,489
Loss from discontinuing operations attributable to MDC Partners Inc., net of taxes	0	(1,316)	0	(6,281)
Net loss	(32,471)	(6,482)	(52,478)	(3,792)
Net income attributable to the noncontrolling interests	(1,059)	(2,122)	(3,172)	(7,343)	$ (9,054)
Net loss attributable to MDC Partners Inc.	(33,530)	(8,604)	(55,650)	(11,135)
Stock-based compensation	5,228	3,266	15,443	13,025
Supplemental Segment Information:
Capital expenditures	6,275	8,161	19,723	17,665
Goodwill and intangibles	961,458	944,702	961,458	944,702
Total Assets	1,642,312	1,603,946	1,642,312	1,603,946	$ 1,577,625
Corporate
Segment Reporting Information [Line Items]
Revenue	0	0	0	0
Cost of services sold	0	0	0	0
Office and general expenses	6,692	19,464	31,716	49,273
Depreciation and amortization	359	337	1,266	1,236
Goodwill, Impairment Loss	0		0
Operating profit	(7,051)	(19,801)	(32,982)	(50,509)
Other Income (Expense):
Net income attributable to the noncontrolling interests	0	0	0	0
Stock-based compensation	605	606	2,059	2,002
Supplemental Segment Information:
Capital expenditures	0	10	32	273
Goodwill and intangibles	0	0	0	0
Total Assets	135,698	124,146	135,698	124,146
Reportable Segment [Domain]
Segment Reporting Information [Line Items]
Revenue	289,988	271,882	822,762	804,399
Cost of services sold	193,677	173,944	558,854	535,278
Office and general expenses	65,407	50,425	171,310	137,403
Depreciation and amortization	10,070	8,095	24,462	24,486
Goodwill, Impairment Loss	0		0
Operating profit	20,834	39,418	68,136	107,232
Other Income (Expense):
Net income attributable to the noncontrolling interests	(962)	(1,366)	(2,604)	(6,010)
Stock-based compensation	3,337	1,857	11,067	7,763
Supplemental Segment Information:
Capital expenditures	5,938	7,650	17,440	16,084
Goodwill and intangibles	751,511	695,839	751,511	695,839
Total Assets	1,214,533	1,155,558	1,214,533	1,155,558
All Other Segment [Domain]
Segment Reporting Information [Line Items]
Revenue	59,266	56,533	172,581	162,844
Cost of services sold	41,982	38,981	117,086	113,108
Office and general expenses	11,204	8,897	30,814	19,493
Depreciation and amortization	983	4,654	8,340	13,671
Goodwill, Impairment Loss	29,631		29,631
Operating profit	(24,534)	4,001	(13,290)	16,572
Other Income (Expense):
Net income attributable to the noncontrolling interests	(97)	(756)	(568)	(1,333)
Stock-based compensation	1,286	803	2,317	3,260
Supplemental Segment Information:
Capital expenditures	337	501	2,251
Goodwill and intangibles	209,947	248,863	209,947	248,863
Total Assets	$ 292,081	$ 324,242	$ 292,081	$ 324,242