Segment Information - Summary of Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 4,674.1		$ 4,674.1		$ 2,981.6
Net revenue	383.1	$ 393.0	1,329.7	$ 1,232.4
Live and Historical Racing:
Segment Reporting, Asset Reconciling Item [Line Items]
Net revenue	102.4	81.5	465.5	336.7
TwinSpires
Segment Reporting, Asset Reconciling Item [Line Items]
Net revenue	107.4	109.0	347.3	356.6
Gaming
Segment Reporting, Asset Reconciling Item [Line Items]
Net revenue	185.9	185.6	549.6	525.6
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,655.0		2,655.0		1,975.6
Net revenue	383.1	393.0	1,329.7	1,232.4
Operating Segments | Live and Historical Racing:
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,051.1		1,051.1		682.7
Net revenue	92.3	79.7	439.2	318.8
Operating Segments | TwinSpires
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	285.2		285.2		289.6
Net revenue	106.2	107.5	343.3	351.8
Operating Segments | Gaming
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,318.7		1,318.7		1,003.3
Net revenue	183.4	185.3	545.0	523.3
All Other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,019.1		2,019.1		$ 1,006.0
Net revenue	$ 1.2	$ 20.5	$ 2.2	$ 38.5