Goodwill and Intangible Assets - Textual (Details)	3 Months Ended		12 Months Ended
	Dec. 31, 2016 USD ($) reportable_segment	Sep. 30, 2016 USD ($) reportable_segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Goodwill [Line Items]
Goodwill, impaired, accumulated impairment loss	$ 95,407,000		$ 95,407,000
Goodwill, Impairment Loss			$ 764,000		$ 15,564
Goodwill, Purchase Accounting Adjustments				$ (2,428,000)
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			7 years
Amortization of intangibles			$ 24,153,000	33,352,000	30,710,000
Goodwill, Impairment Loss			48,524,000	0	0
Indefinite-lived Intangible Assets [Member]
Goodwill [Line Items]
Amortization of intangibles			$ 21,726,000	30,024,000	$ 29,749,000
Customer Relationships
Goodwill [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			6 years
Other Intangible Assets
Goodwill [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			8 years
All Other [Domain]
Goodwill [Line Items]
Goodwill, Impairment Loss			$ 764,000
Goodwill, Purchase Accounting Adjustments				$ (684,000)
Goodwill, Impairment Loss			$ 29,631,000
Experiential [Member] | All Other [Domain]
Goodwill [Line Items]
Reporting Units, Goodwill Impairment Test Performed During Interim Period | reportable_segment		1
Goodwill, Impairment Loss		$ 28,000
Immaterial [Member] | All Other [Domain]
Goodwill [Line Items]
Reporting Units, Goodwill Impairment Test Performed During Interim Period | reportable_segment		1
Goodwill, Impairment Loss		$ 2,000
Strategic Communications [Member]
Goodwill [Line Items]
Goodwill, Impairment Loss	$ 18,893
Strategic Communications [Member] | All Other [Domain]
Goodwill [Line Items]
Reporting Units Impaired, Annual Goodwill Impairment Test | reportable_segment	1