Goodwill - Schedule of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Roll Forward]
Balance, beginning of period	$ 723.8	$ 366.8
Additions	177.1	357.0
Adjustments	(1.0)
Balance, end of period	899.9	723.8
All Other
Goodwill [Roll Forward]
Balance, beginning of period	1.0	1.0
Additions	0.0	0.0
Adjustments	(1.0)
Balance, end of period	0.0	1.0
Live and Historical | Operating Segments
Goodwill [Roll Forward]
Balance, beginning of period	280.3	52.4
Additions	95.9	227.9
Adjustments	0.0
Balance, end of period	376.2	280.3
TwinSpires | Operating Segments
Goodwill [Roll Forward]
Balance, beginning of period	152.2	152.2
Additions	81.2	0.0
Adjustments	0.0
Balance, end of period	233.4	152.2
Gaming | Operating Segments
Goodwill [Roll Forward]
Balance, beginning of period	290.3	161.2
Additions	0.0	129.1
Adjustments	0.0
Balance, end of period	$ 290.3	$ 290.3