Goodwill - Schedule of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Balance, beginning of period	$ 366.8	$ 367.1
Adjustments	0.0	(0.3)
Balance, end of period	366.8	366.8
All Other
Goodwill [Roll Forward]
Balance, beginning of period	1.0	1.0
Adjustments	0.0	0.0
Balance, end of period	1.0	1.0
Live and Historical Racing | Operating Segments
Goodwill [Roll Forward]
Balance, beginning of period	52.4	52.7
Adjustments	0.0	(0.3)
Balance, end of period	52.4	52.4
TwinSpires | Operating Segments
Goodwill [Roll Forward]
Balance, beginning of period	152.2	152.2
Adjustments	0.0	0.0
Balance, end of period	152.2	152.2
Gaming | Operating Segments
Goodwill [Roll Forward]
Balance, beginning of period	161.2	161.2
Adjustments	0.0	0.0
Balance, end of period	$ 161.2	$ 161.2