Segment Information - Summary of Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 4,619.6		$ 4,619.6		$ 2,981.6
Net revenue	582.5	$ 515.1	946.6	$ 839.4
Live and Historical Racing
Segment Reporting, Asset Reconciling Item [Line Items]
Net revenue	275.9	190.5	363.1	255.2
TwinSpires
Segment Reporting, Asset Reconciling Item [Line Items]
Net revenue	138.5	142.6	239.9	247.6
Gaming
Segment Reporting, Asset Reconciling Item [Line Items]
Net revenue	184.5	186.0	363.7	340.0
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,395.6		2,395.6		1,975.6
Net revenue	582.5	515.1	946.6	839.4
Operating Segments | Live and Historical Racing
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	810.8		810.8		682.7
Net revenue	260.9	175.9	346.9	239.1
Operating Segments | TwinSpires
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	296.1		296.1		289.6
Net revenue	136.8	140.8	237.1	244.3
Operating Segments | Gaming
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,288.7		1,288.7		1,003.3
Net revenue	184.3	186.0	361.6	338.0
All Other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,224.0		2,224.0		$ 1,006.0
Net revenue	$ 0.5	$ 12.4	$ 1.0	$ 18.0