Discontinued Operations - Fair Value of Liabilities (Details) - Big Fish Games - Discontinued Operations, Held-for-sale $ in Millions	Dec. 31, 2017 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities measured at fair value on a recurring basis	$ 62.6
Deferred Payments
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities measured at fair value on a recurring basis	28.4
Earnout Liability
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities measured at fair value on a recurring basis	$ 34.2