Business Combination (Details) (USD $)	0 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	Apr. 01, 2014	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Apr. 01, 2014
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross					$ 101,891,000
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Goodwill		164,887,000	130,794,000		164,887,000		164,887,000
Cable Networks Acquisition [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	101,900,000
Costs incurred in connection with acquisition			900,000				1,200,000
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Other assets								177,000
Other liabilities								(2,123,000)
Fair value of identifiable net assets acquired								64,012,000
Goodwill								34,093,000
Total								98,105,000
Pro Forma Information
Net Revenues		28,781,000		29,058,000	84,649,000	76,385,000
Operating Income		6,586,000		5,336,000	18,072,000	13,767,000
Agreement termination charge excluded from reported pro forma results				3,800,000		3,800,000
Net revenues of acquiree included in consolidated statements of operations		5,700,000			11,500,000
Operating income of acquiree included in consolidated statements of operations		1,600,000			3,300,000
Foreign Tax Credits [Member] | Cable Networks Acquisition [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Change in valuation allowance for deferred tax asset	(2,500,000)
Affiliate Relationships [Member] | Cable Networks Acquisition [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Amortizable intangible assets acquired	46,014,000							46,014,000
useful lives					8 years
Affiliate Relationships [Member] | Cable Networks Acquisition [Member] | Discounted Cash Flow Method [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Discount rate (as a percent)	8.50%
Advertiser Relationships [Member] | Cable Networks Acquisition [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Amortizable intangible assets acquired	3,310,000							3,310,000
useful lives					6 years
Advertiser Relationships [Member] | Cable Networks Acquisition [Member] | Discounted Cash Flow Method [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Discount rate (as a percent)	8.50%
Other Intangible Assets [Member] | Cable Networks Acquisition [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Amortizable intangible assets acquired	1,100,000							1,100,000
Other Intangible Assets Excluding Employment Contract [Member] | Cable Networks Acquisition [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Amortizable intangible assets acquired	648,000							648,000
Employment Contracts [Member] | Consulting Agreement With Executives Of Acquiree [Member | Cable Networks Acquisition [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Fair value of identifiable assets accounted for separately from the acquisition	500,000							500,000
Noncompete Agreements [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
useful lives					6 years
Noncompete Agreements [Member] | Noncompete Agreement With Acquiree [Member] | Cable Networks Acquisition [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Fair value of identifiable assets accounted for separately from the acquisition	3,300,000							3,300,000
useful lives					6 years
Noncompete Agreements [Member] | Noncompete Agreement With Acquiree [Member] | Cable Networks Acquisition [Member] | Discounted Cash Flow Method [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Discount rate (as a percent)	8.50%
Maximum [Member] | Affiliate Relationships [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
useful lives					8 years
Maximum [Member] | Other Intangible Assets [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
useful lives					1 year
Maximum [Member] | Other Intangible Assets [Member] | Cable Networks Acquisition [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
useful lives					1 year
Trademarks and Trade Names [Member] | Cable Networks Acquisition [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Indefinite lived intangible assets acquired	$ 15,986,000							$ 15,986,000
Trademarks and Trade Names [Member] | Cable Networks Acquisition [Member] | Discounted Cash Flow Method [Member]
Estimated fair values of assets acquired, liabilities assumed and resulting goodwill
Discount rate (as a percent)	8.50%
Royalty rate (as a percent)	5.00%