Segment Information - Summary of Assets (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 3,036.9	$ 2,981.6	$ 2,981.6
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	2,008.3		1,975.6
Operating Segments | Live and Historical Racing
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	719.0		682.7
Operating Segments | TwinSpires
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	286.0		289.6
Operating Segments | Gaming
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,003.3		1,003.3
All Other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 1,028.6		$ 1,006.0