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, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Net revenue	$ 628.5	$ 572.5	$ 2,110.1	$ 1,900.5
Disclosure of complimentary revenue	14.2	13.3	41.7	37.8
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	269.7	244.3	783.1	740.2
Other
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.2	0.1	0.7
External Customer
Disaggregation of Revenue [Line Items]
Net revenue	628.5	572.5	2,110.1	1,900.5
External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	102.9	107.4	374.6	370.3
External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	215.2	187.4	657.5	569.8
External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	6.4	4.7	187.1	145.8
External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	231.8	211.4	669.4	634.5
External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	72.2	61.6	221.5	180.1
Operating Segments | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	628.5	572.3	2,110.0	1,899.8
Operating Segments | External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	102.9	107.4	374.6	370.3
Operating Segments | External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	215.2	187.4	657.5	569.8
Operating Segments | External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	6.4	4.7	187.1	145.8
Operating Segments | External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	231.8	211.4	669.4	634.5
Operating Segments | External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	72.2	61.4	221.4	179.4
Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	247.5	219.5	957.3	818.9
Operating Segments | Live and Historical | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	4.9	6.0	34.2	30.4
Operating Segments | Live and Historical | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	247.5	219.5	957.3	818.9
Operating Segments | Live and Historical | External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	15.2	16.0	76.6	67.2
Operating Segments | Live and Historical | External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	205.9	179.9	630.1	549.3
Operating Segments | Live and Historical | External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	5.0	3.3	182.1	141.0
Operating Segments | Live and Historical | External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	3.1	3.1	9.5	8.2
Operating Segments | Live and Historical | External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	18.3	17.2	59.0	53.2
Operating Segments | TwinSpires
Disaggregation of Revenue [Line Items]
Net revenue	111.3	108.5	369.6	340.7
Operating Segments | TwinSpires | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	7.4	3.9	23.1	7.1
Operating Segments | TwinSpires | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	111.3	108.5	369.6	340.7
Operating Segments | TwinSpires | External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	82.7	86.3	277.9	283.2
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	4.4	5.3	14.4	10.9
Operating Segments | TwinSpires | External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	24.2	16.9	77.3	46.6
Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	269.7	244.3	783.1	740.2
Operating Segments | Gaming | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	0.6	0.6	4.8	4.2
Operating Segments | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	269.7	244.3	783.1	740.2
Operating Segments | Gaming | External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	5.0	5.1	20.1	19.9
Operating Segments | Gaming | External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	9.3	7.5	27.4	20.5
Operating Segments | Gaming | External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	1.4	1.4	5.0	4.8
Operating Segments | Gaming | External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	224.3	203.0	645.5	615.4
Operating Segments | Gaming | External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	29.7	27.3	85.1	79.6
All Other
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.2	0.1	0.7
All Other | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	2.6	0.0	4.4	0.0
All Other | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.2	0.1	0.7
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	0.0	0.2	0.1	0.7
Eliminations | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	(15.5)	(10.5)	(66.5)	(41.7)
Churchill Downs Racetrack | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	11.7	10.6	242.8	191.3
Louisville | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	50.3	48.9	157.1	138.2
Northern Kentucky | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	23.4	19.5	73.9	63.1
Southwestern Kentucky | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	39.3	37.6	118.1	111.7
Western Kentucky | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	9.8	11.6	22.7	25.8
Virginia | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	110.0	88.1	333.1	280.4
New Hampshire | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	3.0	3.2	9.6	8.4
Florida | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	23.8	24.4	76.4	76.5
Iowa | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	22.9	24.0	69.8	72.5
Indiana | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	32.4	0.0	66.3	0.0
Louisiana | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	32.0	32.2	113.4	110.1
Maine | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	27.7	30.9	81.3	88.1
Maryland | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	31.5	32.0	79.3	82.9
Mississippi | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	23.6	24.2	74.1	77.5
New York | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	46.8	46.2	138.3	135.3
Pennsylvania | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	$ 29.0	$ 30.4	$ 84.2	$ 97.3