Segment Information - Net Revenue From External Customers and Intercompany Revenue From Each Operating Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Net revenue	$ 628.5	$ 572.5	$ 2,110.1	$ 1,900.5
External Customer
Segment Reporting Information [Line Items]
Net revenue	628.5	572.5	2,110.1	1,900.5
Operating Segments | Live and Historical Racing
Segment Reporting Information [Line Items]
Net revenue	247.5	219.5	957.3	818.9
Operating Segments | TwinSpires
Segment Reporting Information [Line Items]
Net revenue	111.3	108.5	369.6	340.7
Operating Segments | Gaming
Segment Reporting Information [Line Items]
Net revenue	269.7	244.3	783.1	740.2
Operating Segments | External Customer
Segment Reporting Information [Line Items]
Net revenue	628.5	572.3	2,110.0	1,899.8
Operating Segments | External Customer | Live and Historical Racing
Segment Reporting Information [Line Items]
Net revenue	247.5	219.5	957.3	818.9
Operating Segments | External Customer | TwinSpires
Segment Reporting Information [Line Items]
Net revenue	111.3	108.5	369.6	340.7
Operating Segments | External Customer | Gaming
Segment Reporting Information [Line Items]
Net revenue	269.7	244.3	783.1	740.2
All Other
Segment Reporting Information [Line Items]
Net revenue	0.0	0.2	0.1	0.7
All Other | External Customer
Segment Reporting Information [Line Items]
Net revenue	$ 0.0	$ 0.2	$ 0.1	$ 0.7