Other Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets (excluding goodwill)	$ 169.4	$ 264.0	$ 169.4
Definite lived intangible assets	19.2	18.0	19.2
Amortization of definite-lived intangible assets		6.0	6.8	$ 9.4
Additional payments not included in future estimated amortization expense		2.3
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Definite lived intangible assets	6.1	3.9	6.1
Other
Finite-Lived Intangible Assets [Line Items]
Definite lived intangible assets	5.6	7.2	5.6
Calder Racing
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired		2.3	2.3
Gaming rights
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets (excluding goodwill)	128.9	216.4	128.9
Trademarks
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets (excluding goodwill)	21.2	29.5	21.2
Illinois Horseracing Equity Trust | Racing
Finite-Lived Intangible Assets [Line Items]
Impairment of indefinite lived intangible assets	3.3
Ocean Downs and Racing Services | Other
Finite-Lived Intangible Assets [Line Items]
Definite lived intangible assets		2.3
Ocean Downs and Racing Services | Gaming rights
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets (excluding goodwill)		87.0
Ocean Downs and Racing Services | Trademarks
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets (excluding goodwill)		8.3
Derby City Gaming | Other
Finite-Lived Intangible Assets [Line Items]
Definite lived intangible assets		$ 0.1
BetAmerica Corporation | Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired			4.7
BetAmerica Corporation | Other
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired			$ 3.4
Bluff Media | Online Wagering
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible assets (excluding goodwill)	4.7
Bluff Media | Online Wagering | Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Impairment of definite lived intangible assets	0.2
Bluff Media | Trademarks | Online Wagering
Finite-Lived Intangible Assets [Line Items]
Impairment of indefinite lived intangible assets	$ 4.5