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Goodwill and Other Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Mar. 31, 2019	Sep. 30, 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		338.2		$ 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 Downs & Casino [Member]
Indefinite-lived Intangible Assets [Line Items]
Goodwill			$ 25.8
Goodwill additions	$ 25.8
Contractual Rights [Member] \| Presque Isle Downs & Casino [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets		56.0
Trademarks \| Presque Isle Downs & Casino [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets		15.2
Gaming \| Contractual Rights [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets		3.0
Online Wagering \| Contractual Rights [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets		8.0
Online Wagering \| Contractual Rights [Member] \| Presque Isle Downs & Casino [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets		$ 10.0