Acquisitions (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended				9 Months Ended	12 Months Ended							0 Months Ended	3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014 Aggregate Year to Date Acquisitions	Dec. 31, 2013 Aggregate Year to Date Acquisitions	Mar. 31, 2014 Aggregate Year to Date Acquisitions	Mar. 31, 2014 Aggregate Year to Date Acquisitions Luntz Global Partners L L C	Mar. 31, 2014 Aggregate Year to Date Acquisitions Kingsdale Partners LP	Sep. 30, 2014 Aggregate Year to Date Acquisitions Hunter PR LLC [Member] [Domain]	Sep. 30, 2014 Aggregate Year to Date Acquisitions Albion Brand Communications Limited [Member] [Domain] [Domain]	Dec. 31, 2013 Aggregate Year to Date Acquisitions Local Biz Now LLC	Jul. 31, 2014 Trapeze Media Limited Union Advertising Canada LC [Member] [Domain]	Sep. 30, 2014 Union Advertising Canada LC [Member] Trapeze Media Limited	Jul. 31, 2014 Union Advertising Canada LC [Member] Trapeze Media Limited
Business Acquisition [Line Items]
business acquisition, current period revenue	$ 18,069		$ 34,049
business acquisition, current period net income	1,791		5,810
Business Acquisition, Increase (Decrease) In Contingent Purchase Price Obligation	2,623	717	14,716	5,400
Business Acquisition, Cost of Acquired Entity, Purchase Price							162,975	38,202
Business Acquisition, Cost of Acquired Entity, Cash Paid							67,238	12,000
Business Acquisition, Deferred Acquisition Consideration							95,737	26,202
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets							33,956	10,835
Business Acquisition, Purchase Price Allocation, Goodwill Amount							188,988	35,956
Nonredeemable Noncontrolling Interest							63,158
Redeemable Noncontrolling Interest, Equity, Fair Value	185,925		185,925		148,534	117,953	13,720
Redeemable Noncontrolling Interest, Equity, Carrying Amount								11,090
Business Acquisition Purchase Price Allocation Intangibles and Goodwill Expected Tax Deductible Amount								46,791	107,793
Business Combination, Step Acquisition Gain on sale of ownership percentage																$ 908
Noncontrolling Interest, Ownership Percentage by Parent	100.00%		100.00%
Sale of Stock, Percentage of Ownership after Transaction															100.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners																	18.00%
Business Acquisition, Percentage of Voting Interests Acquired										60.00%	65.00%	65.00%	75.00%	70.00%