Segment Information - Adjusted EBITDA by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Net revenue	$ 185.1	$ 477.4	$ 438.0	$ 742.8
Churchill Downs
Segment Reporting Information [Line Items]
Net revenue	30.2	193.1	54.0	214.5
Taxes and purses	(13.9)	(35.7)	(21.0)	(41.9)
Marketing and advertising	(0.3)	(3.6)	(1.4)	(4.7)
Salaries and benefits	(4.9)	(12.5)	(11.1)	(17.7)
Content expense	(0.1)	(0.8)	(0.5)	(1.3)
Selling, general and administrative expense	(1.2)	(2.0)	(2.7)	(3.7)
Other operating expense	(5.3)	(16.6)	(10.9)	(21.9)
Other income	0.0	0.0	0.0	0.0
Adjusted EBITDA	4.5	121.9	6.4	123.3
Online Wagering
Segment Reporting Information [Line Items]
Net revenue	121.6	96.0	189.3	159.4
Taxes and purses	(6.6)	(4.3)	(10.5)	(7.6)
Marketing and advertising	(2.9)	(4.5)	(6.4)	(5.5)
Salaries and benefits	(3.0)	(2.7)	(6.5)	(5.2)
Content expense	(59.7)	(51.8)	(92.9)	(83.9)
Selling, general and administrative expense	(1.7)	(1.9)	(3.1)	(3.7)
Other operating expense	(9.0)	(8.6)	(16.2)	(14.4)
Other income	0.1	0.0	0.1	0.0
Adjusted EBITDA	38.8	22.2	53.8	39.1
Gaming
Segment Reporting Information [Line Items]
Net revenue	37.3	177.8	186.4	347.9
Taxes and purses	(14.4)	(68.5)	(73.5)	(133.5)
Marketing and advertising	(0.4)	(5.1)	(5.7)	(10.2)
Salaries and benefits	(9.0)	(25.4)	(38.5)	(49.9)
Content expense	(0.4)	(1.7)	(1.6)	(2.9)
Selling, general and administrative expense	(3.9)	(6.9)	(10.6)	(13.3)
Other operating expense	(11.1)	(21.8)	(30.6)	(40.8)
Other income	(0.1)	27.7	21.1	43.6
Adjusted EBITDA	$ (2.0)	$ 76.1	$ 47.0	$ 140.9