Goodwill and Intangible Assets Intangible Asset Remaining Useful Life (Details)	12 Months Ended
	Dec. 31, 2017
Weighted Average [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	4 years 2 months
Subscriber relationships
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	4 years 10 months 18 days
Distribution rights
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	10 years 3 months 18 days
Internally developed software
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	4 months 24 days
Proprietary content
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	1 year 6 months
Off-Market Favorable Lease
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	1 year 6 months