Segment Information - Summary of Capital Expenditures (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	$ 29.6	$ 131.3
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	27.9	128.5
Operating Segments | Live and Historical Racing
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	16.9	117.9
Operating Segments | TwinSpires
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	4.5	6.1
Operating Segments | Gaming
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	6.5	4.5
All Other
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	$ 1.7	$ 2.8