Acquisitions (Details Textual) (USD $) In Thousands, unless otherwise specified		12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012 Aggregate Year to Date Acquisitions [Member]
Significant Acquisitions and Disposals, Description		During 2012, the Company completed a number of transactions. Effective March 28, 2012, MDC invested in Doner Partners LLC (Doner). The Company acquired a 30% voting interest and a convertible preferred interest that allows the Company to increase ordinary voting ownership to 70% at MDCs option, at no additional cost to the Company. Doner is a full service integrated creative agency. In addition, the Company acquired a 70% interest in TargetCast LLC (TargetCast). TargetCast is a full service media agency that expands our media strategy and activation offerings. The Company acquired a 51% interest in Dotbox LLC (Dotbox), and subsequently acquired the remaining 49% of the equity interests in Dotbox
Business Acquisition, Cost of Acquired Entity, Purchase Price		$ 99,299
Business Acquisition, Cost of Acquired Entity, Cash Paid		23,471
Business Acquisition, Deferred Acquisition Consideration		67,812
Business Acquisition, Working Capital Payments		8,016
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets		31,968
Business Acquisition, Purchase Price Allocation, Goodwill Amount		113,404
Redeemable Noncontrolling Interest, Equity, Carrying Amount		18,501
Business Acquisition Purchase Price Allocation Intangibles and Goodwill Expected Tax Deductible Amount		145,372
Reduction to Short Term Noncontrolling Interest		197
Decrease in Redeemable Noncontrolling Interest		12,523
Step Up Adjustment to Paid in Capital		$ 13,920
Noncontrolling Interest, Ownership Percentage by Parent	100.00%