Discontinued Operations - Major Classes of Assets and Liabilities Derecognized (Details) - USD ($) $ in Millions	Mar. 31, 2018	Jan. 09, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Carrying value of Big Fish Games	$ 751.2
Discontinued Operations, Disposed of by Sale | Big Fish Games
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents		$ 0.3
Accounts receivable		34.7
Game software development, net		6.7
Other current assets		17.0
Property and equipment, net		17.8
Game software development, net		13.8
Goodwill		530.7
Other intangible assets, net		238.4
Other assets		24.0
Accounts payable		(8.5)
Accrued expense		(22.6)
Deferred revenue		(44.2)
Deferred income taxes		(52.0)
Other liabilities		(4.9)
Carrying value of Big Fish Games		$ 751.2