Revenue from Contracts with Customers - Net Revenue From External Customers and Intercompany Revenue From Each Operating Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Net revenue	$ 572.5	$ 383.1	$ 1,900.5	$ 1,329.7
Disclosure of complimentary revenue	13.3	8.4	37.8	23.2
External Customer
Disaggregation of Revenue [Line Items]
Net revenue	572.5	383.1	1,900.5	1,329.7
Related Party
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
Pari-mutuel, live and simulcast racing | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	107.4	96.4	370.3	366.8
Pari-mutuel, historical racing | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	187.4	82.2	569.8	235.5
Racing event-related services | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	4.7	3.1	145.8	126.1
Gaming
Disaggregation of Revenue [Line Items]
Net revenue	244.3	183.4	740.2	545.0
Gaming | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	211.4	166.8	634.5	492.3
Other
Disaggregation of Revenue [Line Items]
Net revenue	0.2	1.2	0.7	2.2
Other | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	61.6	34.6	180.1	109.0
Operating Segments | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	572.3	381.9	1,899.8	1,327.5
Operating Segments | Pari-mutuel, live and simulcast racing | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	107.4	96.4	370.3	366.8
Operating Segments | Pari-mutuel, historical racing | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	187.4	82.2	569.8	235.5
Operating Segments | Racing event-related services | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	4.7	3.1	145.8	126.1
Operating Segments | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	211.4	166.8	634.5	492.3
Operating Segments | Other | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	61.4	33.4	179.4	106.8
Operating Segments | Live and Historical Racing
Disaggregation of Revenue [Line Items]
Net revenue	219.5	92.3	818.9	439.2
Operating Segments | Live and Historical Racing | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	219.5	92.3	818.9	439.2
Operating Segments | Live and Historical Racing | Churchill Downs Racetrack
Disaggregation of Revenue [Line Items]
Net revenue	10.6	6.4	191.3	182.6
Operating Segments | Live and Historical Racing | Louisville
Disaggregation of Revenue [Line Items]
Net revenue	48.9	41.5	138.2	128.5
Operating Segments | Live and Historical Racing | Northern Kentucky
Disaggregation of Revenue [Line Items]
Net revenue	19.5	10.0	63.1	29.2
Operating Segments | Live and Historical Racing | Southwestern Kentucky
Disaggregation of Revenue [Line Items]
Net revenue	37.6	33.3	111.7	97.8
Operating Segments | Live and Historical Racing | Western Kentucky
Disaggregation of Revenue [Line Items]
Net revenue	11.6	0.2	25.8	0.2
Operating Segments | Live and Historical Racing | Virginia
Disaggregation of Revenue [Line Items]
Net revenue	88.1	0.0	280.4	0.0
Operating Segments | Live and Historical Racing | New Hampshire
Disaggregation of Revenue [Line Items]
Net revenue	3.2	0.9	8.4	0.9
Operating Segments | Live and Historical Racing | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	6.0	10.1	30.4	26.3
Operating Segments | Live and Historical Racing | Pari-mutuel, live and simulcast racing | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	16.0	1.8	67.2	53.9
Operating Segments | Live and Historical Racing | Pari-mutuel, historical racing | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	179.9	78.7	549.3	230.7
Operating Segments | Live and Historical Racing | Racing event-related services | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	3.3	3.0	141.0	125.4
Operating Segments | Live and Historical Racing | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	3.1	0.9	8.2	0.9
Operating Segments | Live and Historical Racing | Other | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	17.2	7.9	53.2	28.3
Operating Segments | TwinSpires
Disaggregation of Revenue [Line Items]
Net revenue	108.5	106.2	340.7	343.3
Operating Segments | TwinSpires | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	108.5	106.2	340.7	343.3
Operating Segments | TwinSpires | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	3.9	1.2	7.1	4.0
Operating Segments | TwinSpires | Pari-mutuel, live and simulcast racing | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	86.3	91.0	283.2	290.9
Operating Segments | TwinSpires | Pari-mutuel, historical racing | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
Operating Segments | TwinSpires | Racing event-related services | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
Operating Segments | TwinSpires | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	5.3	5.3	10.9	21.8
Operating Segments | TwinSpires | Other | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	16.9	9.9	46.6	30.6
Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	244.3	183.4	740.2	545.0
Operating Segments | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	244.3	183.4	740.2	545.0
Operating Segments | Gaming | Florida
Disaggregation of Revenue [Line Items]
Net revenue	24.4	26.3	76.5	81.2
Operating Segments | Gaming | Iowa
Disaggregation of Revenue [Line Items]
Net revenue	24.0	0.0	72.5	0.0
Operating Segments | Gaming | Louisiana
Disaggregation of Revenue [Line Items]
Net revenue	32.2	28.5	110.1	107.2
Operating Segments | Gaming | Maine
Disaggregation of Revenue [Line Items]
Net revenue	30.9	31.6	88.1	87.8
Operating Segments | Gaming | Maryland
Disaggregation of Revenue [Line Items]
Net revenue	32.0	33.3	82.9	82.0
Operating Segments | Gaming | Mississippi
Disaggregation of Revenue [Line Items]
Net revenue	24.2	24.5	77.5	78.0
Operating Segments | Gaming | New York
Disaggregation of Revenue [Line Items]
Net revenue	46.2	0.0	135.3	0.0
Operating Segments | Gaming | Pennsylvania
Disaggregation of Revenue [Line Items]
Net revenue	30.4	39.2	97.3	108.8
Operating Segments | Gaming | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	0.6	2.5	4.2	4.6
Operating Segments | Gaming | Pari-mutuel, live and simulcast racing | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	5.1	3.6	19.9	22.0
Operating Segments | Gaming | Pari-mutuel, historical racing | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	7.5	3.5	20.5	4.8
Operating Segments | Gaming | Racing event-related services | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	1.4	0.1	4.8	0.7
Operating Segments | Gaming | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	203.0	160.6	615.4	469.6
Operating Segments | Gaming | Other | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	27.3	15.6	79.6	47.9
All Other
Disaggregation of Revenue [Line Items]
Net revenue	0.2	1.2	0.7	2.2
All Other | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	0.2	1.2	0.7	2.2
All Other | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
All Other | Pari-mutuel, live and simulcast racing | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
All Other | Pari-mutuel, historical racing | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
All Other | Racing event-related services | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
All Other | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
All Other | Other | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	0.2	1.2	0.7	2.2
Eliminations | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	$ (10.5)	$ (13.8)	$ (41.7)	$ (34.9)