Fair Value Of Assets And Liabilities - Level 3 Investment Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value of Level 3 Investments Rollforward
Big Fish Games deferred payments, payments	$ 26.4	$ 28.5	$ 0.0
Change in fair value	5.7	21.7
Fair Value, Inputs, Level 3
Fair Value of Level 3 Investments Rollforward
Big Fish Games deferred payments, beginning balance	54.8
Big Fish Games earnout liability, beginning balance	345.2
Bluff contingent consideration, beginning balance	2.3
Total, beginning balance	402.3
Big Fish Games deferred payments, payments	(28.4)
Big Fish Games earnout liability, payments	(281.6)
Payments	(310.0)
Big Fish Games deferred payments, change in fair value	1.4
Big Fish Games earnout liability, change in fair value	4.3
Bluff contingent consideration, change in fair value	(2.3)
Change in fair value	3.4
Big Fish Games deferred payments, ending balance	27.8	54.8
Big Fish Games earnout liability, ending balance	67.9	345.2
Bluff contingent consideration, ending balance	0.0	2.3
Total, ending balance	$ 95.7	$ 402.3