Segment Information - Summary of Capital Expenditures (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	$ 52.1	$ 210.1
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	49.5	205.6
Operating Segments | Live and Historical Racing
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	32.3	190.9
Operating Segments | TwinSpires
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	7.9	9.6
Operating Segments | Gaming
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	9.3	5.1
All Other
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	$ 2.6	$ 4.5