Revenue from Contracts with Customers - Net Revenue From External Customers and Intercompany Revenue From Each Operating Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total net revenue	$ 2,461.7	$ 1,809.8	$ 1,597.2
Other revenue	50.9	33.9	20.9
External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	2,461.7	1,809.8	1,597.2
Related Party
Disaggregation of Revenue [Line Items]
Total net revenue	0.0	0.0	0.0
Live and simulcast racing | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	468.2	462.3	502.6
Historical racing | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	767.7	383.9	253.0
Racing event-related services | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	152.3	131.6	76.7
Gaming
Disaggregation of Revenue [Line Items]
Total net revenue	968.6	755.9	695.4
Gaming | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	832.2	679.1	656.8
All Other
Disaggregation of Revenue [Line Items]
Total net revenue	0.9	2.9	41.3
All Other | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	241.3	152.9	108.1
Operating Segments | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	2,460.8	1,806.9	1,555.9
Operating Segments | Live and simulcast racing | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	468.2	462.3	472.9
Operating Segments | Historical racing | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	767.7	383.9	253.0
Operating Segments | Racing event-related services | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	152.3	131.6	69.7
Operating Segments | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	832.2	679.1	656.8
Operating Segments | All Other | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	240.4	150.0	103.5
Operating Segments | Live and Historical Racing
Disaggregation of Revenue [Line Items]
Total net revenue	1,047.3	614.6	409.1
Operating Segments | Live and Historical Racing | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	1,047.3	614.6	409.1
Operating Segments | Live and Historical Racing | Churchill Downs Racetrack
Disaggregation of Revenue [Line Items]
Total net revenue	205.8	196.8	128.1
Operating Segments | Live and Historical Racing | Louisville Property
Disaggregation of Revenue [Line Items]
Total net revenue	189.0	169.9	154.3
Operating Segments | Live and Historical Racing | Northern Kentucky
Disaggregation of Revenue [Line Items]
Total net revenue	85.8	46.1	26.0
Operating Segments | Live and Historical Racing | Southwestern Kentucky
Disaggregation of Revenue [Line Items]
Total net revenue	147.8	131.4	100.7
Operating Segments | Live and Historical Racing | Western Kentucky
Disaggregation of Revenue [Line Items]
Total net revenue	31.8	4.5	0.0
Operating Segments | Live and Historical Racing | Virginia
Disaggregation of Revenue [Line Items]
Total net revenue	375.4	62.4	0.0
Operating Segments | Live and Historical Racing | New Hampshire
Disaggregation of Revenue [Line Items]
Total net revenue	11.7	3.5	0.0
Operating Segments | Live and Historical Racing | Related Party
Disaggregation of Revenue [Line Items]
Total net revenue	37.3	31.8	21.5
Operating Segments | Live and Historical Racing | Live and simulcast racing | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	81.9	66.8	64.0
Operating Segments | Live and Historical Racing | Historical racing | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	739.1	374.1	253.0
Operating Segments | Live and Historical Racing | Racing event-related services | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	145.9	129.8	68.5
Operating Segments | Live and Historical Racing | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	11.4	3.5	0.0
Operating Segments | Live and Historical Racing | All Other | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	69.0	40.4	23.6
Operating Segments | TwinSpires
Disaggregation of Revenue [Line Items]
Total net revenue	444.9	436.4	451.4
Operating Segments | TwinSpires | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	444.9	436.4	451.4
Operating Segments | TwinSpires | Related Party
Disaggregation of Revenue [Line Items]
Total net revenue	13.5	5.2	6.4
Operating Segments | TwinSpires | Live and simulcast racing | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	359.7	367.4	380.7
Operating Segments | TwinSpires | Historical racing | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	0.0	0.0	0.0
Operating Segments | TwinSpires | Racing event-related services | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	0.0	0.0	0.0
Operating Segments | TwinSpires | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	17.3	28.2	34.8
Operating Segments | TwinSpires | All Other | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	67.9	40.8	35.9
Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Total net revenue	968.6	755.9	695.4
Operating Segments | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	968.6	755.9	695.4
Operating Segments | Gaming | Florida
Disaggregation of Revenue [Line Items]
Total net revenue	100.7	106.2	100.0
Operating Segments | Gaming | Iowa
Disaggregation of Revenue [Line Items]
Total net revenue	96.0	15.6	0.0
Operating Segments | Gaming | Louisiana
Disaggregation of Revenue [Line Items]
Total net revenue	145.6	140.8	133.6
Operating Segments | Gaming | Maine
Disaggregation of Revenue [Line Items]
Total net revenue	114.1	114.4	99.8
Operating Segments | Gaming | Maryland
Disaggregation of Revenue [Line Items]
Total net revenue	106.9	105.3	100.6
Operating Segments | Gaming | Mississippi
Disaggregation of Revenue [Line Items]
Total net revenue	100.9	101.8	117.3
Operating Segments | Gaming | New York
Disaggregation of Revenue [Line Items]
Total net revenue	180.5	30.9	0.0
Operating Segments | Gaming | Pennsylvania
Disaggregation of Revenue [Line Items]
Total net revenue	123.9	140.9	144.1
Operating Segments | Gaming | Related Party
Disaggregation of Revenue [Line Items]
Total net revenue	6.0	5.9	3.0
Operating Segments | Gaming | Live and simulcast racing | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	26.6	28.1	28.2
Operating Segments | Gaming | Historical racing | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	28.6	9.8	0.0
Operating Segments | Gaming | Racing event-related services | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	6.4	1.8	1.2
Operating Segments | Gaming | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	803.5	647.4	622.0
Operating Segments | Gaming | All Other | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	103.5	68.8	44.0
All Other
Disaggregation of Revenue [Line Items]
Total net revenue	0.9	2.9	41.3
All Other | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	0.9	2.9	41.3
All Other | Related Party
Disaggregation of Revenue [Line Items]
Total net revenue	0.0	0.4	7.9
All Other | Live and simulcast racing | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	0.0	0.0	29.7
All Other | Historical racing | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	0.0	0.0	0.0
All Other | Racing event-related services | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	0.0	0.0	7.0
All Other | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	0.0	0.0	0.0
All Other | All Other | External Customer
Disaggregation of Revenue [Line Items]
Total net revenue	0.9	2.9	4.6
Eliminations | Related Party
Disaggregation of Revenue [Line Items]
Total net revenue	$ (56.8)	$ (43.3)	$ (38.8)