Segment Information - Net Revenue From External Customers and Intercompany Revenue From Each Operating Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Net revenue	$ 559.5	$ 364.1
Live and Historical
Segment Reporting Information [Line Items]
Net revenue	215.8	87.2
TwinSpires
Segment Reporting Information [Line Items]
Net revenue	96.3	101.4
Gaming
Segment Reporting Information [Line Items]
Net revenue	251.6	179.2
External Customer
Segment Reporting Information [Line Items]
Net revenue	559.5	364.1
Operating Segments | Live and Historical
Segment Reporting Information [Line Items]
Net revenue	214.4	86.0
Operating Segments | TwinSpires
Segment Reporting Information [Line Items]
Net revenue	94.8	100.3
Operating Segments | Gaming
Segment Reporting Information [Line Items]
Net revenue	250.0	177.3
Operating Segments | External Customer
Segment Reporting Information [Line Items]
Net revenue	559.2	363.6
Operating Segments | External Customer | Live and Historical
Segment Reporting Information [Line Items]
Net revenue	214.4	86.0
Operating Segments | External Customer | TwinSpires
Segment Reporting Information [Line Items]
Net revenue	94.8	100.3
Operating Segments | External Customer | Gaming
Segment Reporting Information [Line Items]
Net revenue	250.0	177.3
All Other
Segment Reporting Information [Line Items]
Net revenue	0.3	0.5
All Other | External Customer
Segment Reporting Information [Line Items]
Net revenue	$ 0.3	$ 0.5