Revenue from Contracts with Customers - Net Revenue From External Customers and Intercompany Revenue From Each Operating Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Net revenue	$ 890.7	$ 768.5	$ 1,481.6	$ 1,328.0
Disclosure of complimentary revenue	14.2	12.3	27.6	24.5
Related Party
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
Gaming
Disaggregation of Revenue [Line Items]
Net revenue	274.2	245.9	513.4	495.9
Other
Disaggregation of Revenue [Line Items]
Net revenue	0.1	0.2	0.1	0.5
External Customer
Disaggregation of Revenue [Line Items]
Net revenue	890.7	768.5	1,481.6	1,328.0
External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	170.3	160.9	271.7	262.9
External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	221.4	191.1	442.3	382.4
External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	177.4	138.2	180.7	141.1
External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	235.7	210.6	437.6	423.1
External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	85.9	67.7	149.3	118.5
Operating Segments | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	890.6	768.3	1,481.5	1,327.5
Operating Segments | External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	170.3	160.9	271.7	262.9
Operating Segments | External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	221.4	191.1	442.3	382.4
Operating Segments | External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	177.4	138.2	180.7	141.1
Operating Segments | External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	235.7	210.6	437.6	423.1
Operating Segments | External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	85.8	67.5	149.2	118.0
Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	464.7	385.0	709.8	599.4
Operating Segments | Live and Historical | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	25.5	23.0	29.3	24.4
Operating Segments | Live and Historical | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	464.7	385.0	709.8	599.4
Operating Segments | Live and Historical | External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	50.4	40.2	61.4	51.2
Operating Segments | Live and Historical | External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	212.1	184.1	424.2	369.4
Operating Segments | Live and Historical | External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	176.0	136.7	177.1	137.7
Operating Segments | Live and Historical | External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	3.3	2.5	6.4	5.1
Operating Segments | Live and Historical | External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	22.9	21.5	40.7	36.0
Operating Segments | TwinSpires
Disaggregation of Revenue [Line Items]
Net revenue	151.7	137.4	258.3	232.2
Operating Segments | TwinSpires | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	8.2	1.7	15.7	3.3
Operating Segments | TwinSpires | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	151.7	137.4	258.3	232.2
Operating Segments | TwinSpires | External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	115.4	117.5	195.2	196.9
Operating Segments | TwinSpires | External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
Operating Segments | TwinSpires | External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
Operating Segments | TwinSpires | External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	4.3	1.2	10.0	5.6
Operating Segments | TwinSpires | External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	32.0	18.7	53.1	29.7
Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	274.2	245.9	513.4	495.9
Operating Segments | Gaming | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	0.2	2.0	4.2	3.6
Operating Segments | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	274.2	245.9	513.4	495.9
Operating Segments | Gaming | External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	4.5	3.2	15.1	14.8
Operating Segments | Gaming | External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	9.3	7.0	18.1	13.0
Operating Segments | Gaming | External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	1.4	1.5	3.6	3.4
Operating Segments | Gaming | External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	228.1	206.9	421.2	412.4
Operating Segments | Gaming | External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	30.9	27.3	55.4	52.3
All Other
Disaggregation of Revenue [Line Items]
Net revenue	0.1	0.2	0.1	0.5
All Other | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	1.8	0.0	1.8	0.0
All Other | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	0.1	0.2	0.1	0.5
All Other | External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
All Other | External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
All Other | External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
All Other | External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
All Other | External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	0.1	0.2	0.1	0.5
Eliminations | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	(35.7)	(26.7)	(51.0)	(31.3)
Churchill Downs Racetrack | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	228.0	178.3	231.1	180.7
Louisville | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	53.1	45.3	106.8	89.3
Northern Kentucky | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	22.0	17.3	50.5	43.6
Southwestern Kentucky | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	40.2	37.6	78.8	74.1
Western Kentucky | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	6.1	9.4	12.9	14.2
Virginia | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	111.9	94.6	223.1	192.3
New Hampshire | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	3.4	2.5	6.6	5.2
Florida | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	26.5	26.0	52.6	52.1
Iowa | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	23.5	24.0	46.9	48.5
Indiana | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	33.9	0.0	33.9	0.0
Louisiana | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	37.1	33.8	81.4	77.9
Maine | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	26.8	29.5	53.6	57.2
Maryland | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	26.2	27.6	47.8	50.9
Mississippi | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	24.5	25.8	50.5	53.3
New York | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	46.5	44.6	91.5	89.1
Pennsylvania | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	$ 29.2	$ 34.6	$ 55.2	$ 66.9