Goodwill And Indefinite-Lived Intangible Assets Impairment Test Intangible Table (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 180.4	$ 187.4
Finite-Lived Intangible Assets, Accumulated Amortization	(113.3)	(100.0)
Finite-Lived Intangible Assets, Net	67.1	87.4
Indefinite-Lived Intangible Assets (Excluding Goodwill)	358.3	358.3
Other intangible assets, net	425.4	$ 445.7
Customer Relationships [Member] | TwinSpires [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Period Increase (Decrease)	(15.1)
TwinSpires [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 8.1