Basis of Presentations and Summary of Significant Accounting Policies - Intangible Assets (Details) - Media content - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Intangible Assets
Intangibles, useful life	5 years
Accelerated amortization of intangible assets	$ 0.7	$ 1.9	$ 3.4

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