Goodwill And Indefinite-Lived Intangible Assets Impairment Test Goodwill (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill	$ 848.3	$ 832.2
Goodwill, Acquired During Period	16.1
Racing Segment [Member]
Goodwill [Line Items]
Goodwill	51.7	51.7
Goodwill, Acquired During Period	0.0
Casino Segment [Member]
Goodwill [Line Items]
Goodwill	117.6	117.6
Goodwill, Acquired During Period	0.0
TwinSpires [Member]
Goodwill [Line Items]
Goodwill	148.2	132.1
Goodwill, Acquired During Period	16.1
Big Fish Games [Member]
Goodwill [Line Items]
Goodwill	530.8	$ 530.8
Goodwill, Acquired During Period	$ 0.0