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Goodwill and Other Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Jan. 11, 2019	Dec. 31, 2018
Indefinite-lived Intangible Assets [Line Items]
Goodwill	$ 363.8		$ 338.0
Goodwill additions	25.8
Indefinite-lived intangible assets	328.2		$ 246.0
Racing Segment
Indefinite-lived Intangible Assets [Line Items]
Goodwill	51.7
Churchill Downs
Indefinite-lived Intangible Assets [Line Items]
Goodwill	49.7
Gaming
Indefinite-lived Intangible Assets [Line Items]
Goodwill	1.0
Arlington Reporting Unit
Indefinite-lived Intangible Assets [Line Items]
Goodwill	1.0
Presque Isle
Indefinite-lived Intangible Assets [Line Items]
Goodwill		$ 25.8
Goodwill additions	25.8
Gaming Rights \| Presque Isle
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	56.0
Trademarks \| Presque Isle
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	15.2
Gaming \| Gaming Rights
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	3.0
Online Wagering \| Gaming Rights
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 8.0