Segment Information - Net Revenue From External Customers and Intercompany Revenue From Each Operating Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Net revenue	$ 890.7	$ 768.5	$ 1,481.6	$ 1,328.0
External Customer
Segment Reporting Information [Line Items]
Net revenue	890.7	768.5	1,481.6	1,328.0
Operating Segments | Live and Historical
Segment Reporting Information [Line Items]
Net revenue	464.7	385.0	709.8	599.4
Operating Segments | TwinSpires
Segment Reporting Information [Line Items]
Net revenue	151.7	137.4	258.3	232.2
Operating Segments | Gaming
Segment Reporting Information [Line Items]
Net revenue	274.2	245.9	513.4	495.9
Operating Segments | External Customer
Segment Reporting Information [Line Items]
Net revenue	890.6	768.3	1,481.5	1,327.5
Operating Segments | External Customer | Live and Historical
Segment Reporting Information [Line Items]
Net revenue	464.7	385.0	709.8	599.4
Operating Segments | External Customer | TwinSpires
Segment Reporting Information [Line Items]
Net revenue	151.7	137.4	258.3	232.2
Operating Segments | External Customer | Gaming
Segment Reporting Information [Line Items]
Net revenue	274.2	245.9	513.4	495.9
All Other
Segment Reporting Information [Line Items]
Net revenue	0.1	0.2	0.1	0.5
All Other | External Customer
Segment Reporting Information [Line Items]
Net revenue	$ 0.1	$ 0.2	$ 0.1	$ 0.5