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, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Net revenue	$ 768.5	$ 582.5	$ 1,328.0	$ 946.6
Disclosure of complimentary revenue	12.3	7.7	24.5	14.8
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	245.9	184.3	495.9	361.6
Other
Disaggregation of Revenue [Line Items]
Net revenue	0.2	0.5	0.5	1.0
External Customer
Disaggregation of Revenue [Line Items]
Net revenue	768.5	582.5	1,328.0	946.6
External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	160.9	170.4	262.9	270.4
External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	191.1	79.7	382.4	153.3
External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	138.2	122.1	141.1	123.0
External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	210.6	164.3	423.1	325.5
External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	67.7	46.0	118.5	74.4
Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	408.0	275.9	623.8	363.1
TwinSpires
Disaggregation of Revenue [Line Items]
Net revenue	139.1	138.5	235.5	239.9
Gaming
Disaggregation of Revenue [Line Items]
Net revenue	247.9	184.5	499.5	363.7
Operating Segments | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	768.3	582.0	1,327.5	945.6
Operating Segments | External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	160.9	170.4	262.9	270.4
Operating Segments | External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	191.1	79.7	382.4	153.3
Operating Segments | External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	138.2	122.1	141.1	123.0
Operating Segments | External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	210.6	164.3	423.1	325.5
Operating Segments | External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	67.5	45.5	118.0	73.4
Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	385.0	260.9	599.4	346.9
Operating Segments | Live and Historical | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	23.0	15.0	24.4	16.2
Operating Segments | Live and Historical | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	385.0	260.9	599.4	346.9
Operating Segments | Live and Historical | External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	40.2	46.5	51.2	52.1
Operating Segments | Live and Historical | External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	184.1	78.4	369.4	152.0
Operating Segments | Live and Historical | External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	136.7	121.9	137.7	122.4
Operating Segments | Live and Historical | External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	2.5	0.0	5.1	0.0
Operating Segments | Live and Historical | External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	21.5	14.1	36.0	20.4
Operating Segments | TwinSpires
Disaggregation of Revenue [Line Items]
Net revenue	137.4	136.8	232.2	237.1
Operating Segments | TwinSpires | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	1.7	1.7	3.3	2.8
Operating Segments | TwinSpires | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	137.4	136.8	232.2	237.1
Operating Segments | TwinSpires | External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	117.5	118.4	196.9	199.9
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	1.2	6.2	5.6	16.5
Operating Segments | TwinSpires | External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	18.7	12.2	29.7	20.7
Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	245.9	184.3	495.9	361.6
Operating Segments | Gaming | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	2.0	0.2	3.6	2.1
Operating Segments | Gaming | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	245.9	184.3	495.9	361.6
Operating Segments | Gaming | External Customer | Pari-mutuel, live and simulcast racing
Disaggregation of Revenue [Line Items]
Net revenue	3.2	5.5	14.8	18.4
Operating Segments | Gaming | External Customer | Pari-mutuel, historical racing
Disaggregation of Revenue [Line Items]
Net revenue	7.0	1.3	13.0	1.3
Operating Segments | Gaming | External Customer | Racing event-related services
Disaggregation of Revenue [Line Items]
Net revenue	1.5	0.2	3.4	0.6
Operating Segments | Gaming | External Customer | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	206.9	158.1	412.4	309.0
Operating Segments | Gaming | External Customer | Other
Disaggregation of Revenue [Line Items]
Net revenue	27.3	19.2	52.3	32.3
All Other
Disaggregation of Revenue [Line Items]
Net revenue	0.2	0.5	0.5	1.0
All Other | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	0.0	0.0	0.0	0.0
All Other | External Customer
Disaggregation of Revenue [Line Items]
Net revenue	0.2	0.5	0.5	1.0
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	0.2	0.5	0.5	1.0
Eliminations | Related Party
Disaggregation of Revenue [Line Items]
Net revenue	(26.7)	(16.9)	(31.3)	(21.1)
Churchill Downs Racetrack | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	178.3	174.2	180.7	176.2
Louisville | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	45.3	44.2	89.3	87.0
Northern Kentucky | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	17.3	8.4	43.6	19.2
Southwestern Kentucky | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	37.6	34.1	74.1	64.5
Western Kentucky | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	9.4	0.0	14.2	0.0
Virginia | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	94.6	0.0	192.3	0.0
New Hampshire | Operating Segments | Live and Historical
Disaggregation of Revenue [Line Items]
Net revenue	2.5	0.0	5.2	0.0
Florida | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	26.0	27.9	52.1	54.9
Iowa | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	24.0	0.0	48.5	0.0
Louisiana | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	33.8	37.2	77.9	78.7
Maine | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	29.5	29.4	57.2	56.2
Maryland | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	27.6	27.4	50.9	48.7
Mississippi | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	25.8	26.0	53.3	53.5
New York | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	44.6	0.0	89.1	0.0
Pennsylvania | Operating Segments | Gaming
Disaggregation of Revenue [Line Items]
Net revenue	$ 34.6	$ 36.4	$ 66.9	$ 69.6