Segment Information - Summary of Capital Expenditures (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	$ 12.3	$ 48.3
Operating Segments | Total Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	11.7	46.5
Operating Segments | Live and Historical Racing
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	7.8	39.7
Operating Segments | TwinSpires
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	2.3	3.5
Operating Segments | Gaming
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	1.6	3.3
Segment Reconciling Items
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	$ 0.6	$ 1.8