Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenue	$ 336,606	$ 299,356	$ 638,828	$ 574,210
Cost of services sold	225,042	188,875	435,461	370,343
Office and general expenses	53,075	71,436	127,383	142,772
Depreciation and amortization	14,007	9,917	26,307	20,399
Operating Profit (Loss)	44,482	29,128	49,677	40,696
Other Income (Expense):
Other income, net	4,348	7,564	(13,692)	993
Interest expense, net	(13,183)	(13,840)	(28,160)	(26,459)
Loss from continuing operations before income taxes, equity in affiliates	35,647	22,852	7,825	15,230
Income tax benefit	4,679	3,376	625	3,030
Loss from continuing operations before equity in affiliates	30,968	19,476	7,200	12,200
Equity in earnings of non-consolidated affiliates	104	79	455	142
Income from continuing operations	31,072	19,555	7,655	12,342
Loss from discontinuing operations attributable to MDC Partners Inc., net of taxes	1,329	(1,336)	(4,965)	(1,607)
Net income	32,401	18,219	2,690	10,735
Net income attributable to the noncontrolling interests	(2,841)	(1,749)	(5,221)	(3,111)	$ (6,890)
Net loss attributable to MDC Partners Inc.	29,560	16,470	(2,531)	7,624
Stock based compensation	5,314	4,428	9,759	8,796
Supplemental Segment Information:
Capital expenditures	3,848	3,204	9,504	5,700
Goodwill and intangibles	961,860	951,484	961,860	951,484
Total Assets	1,848,647	1,685,018	1,848,647	1,685,018	$ 1,648,890
Strategic Marketing Services
Segment Reporting Information [Line Items]
Revenue	270,091	230,117	510,527	444,921
Cost of services sold	181,231	145,679	347,257	286,239
Office and general expenses	48,934	43,352	98,090	88,398
Depreciation and amortization	6,492	5,139	12,915	10,287
Operating Profit (Loss)	33,434	35,947	52,265	59,997
Other Income (Expense):
Net income attributable to the noncontrolling interests	(2,754)	(1,860)	(5,047)	(3,250)
Stock based compensation	4,087	2,112	6,611	4,251
Supplemental Segment Information:
Capital expenditures	3,229	2,393	8,559	4,095
Goodwill and intangibles	552,222	516,815	552,222	516,815
Total Assets	901,423	876,251	901,423	876,251
Performance Marketing Services
Segment Reporting Information [Line Items]
Revenue	66,515	69,239	128,301	129,289
Cost of services sold	43,811	43,196	88,204	84,104
Office and general expenses	655	15,971	11,809	32,286
Depreciation and amortization	5,790	4,345	11,220	9,177
Operating Profit (Loss)	16,259	5,727	17,068	3,722
Other Income (Expense):
Net income attributable to the noncontrolling interests	(87)	111	(174)	139
Stock based compensation	838	930	1,959	2,207
Supplemental Segment Information:
Capital expenditures	424	546	682	799
Goodwill and intangibles	409,638	434,669	409,638	434,669
Total Assets	756,535	605,315	756,535	605,315
Corporate
Segment Reporting Information [Line Items]
Revenue	0	0	0	0
Cost of services sold	0	0	0	0
Office and general expenses	3,486	12,113	17,484	22,088
Depreciation and amortization	1,725	433	2,172	935
Operating Profit (Loss)	(5,211)	(12,546)	(19,656)	(23,023)
Other Income (Expense):
Net income attributable to the noncontrolling interests	0	0	0	0
Stock based compensation	389	1,386	1,189	2,338
Supplemental Segment Information:
Capital expenditures	195	265	263	806
Goodwill and intangibles	0	0	0	0
Total Assets	$ 190,689	$ 203,452	$ 190,689	$ 203,452