Segment Information - Adjusted EBITDA by Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Other charges & recoveries, net	$ 0.1	$ 0.0	$ 0.0	$ 0.0
Net revenue	306.3	221.3	1,049.1	790.0
Churchill Downs
Segment Reporting Information [Line Items]
Net revenue	32.7	11.8	247.2	178.4
Taxes and purses	(10.2)	(3.6)	(52.1)	(31.6)
Marketing and advertising	(1.1)	(0.6)	(5.8)	(4.1)
Salaries and benefits	(6.8)	(4.5)	(24.5)	(17.3)
Content Expense	(0.5)	(0.5)	(1.8)	(1.8)
Adjusted EBITDA Selling, General & Administrative Expenses	(2.1)	(0.8)	(5.8)	(3.0)
Other Cost and Expense, Operating	(6.9)	(4.6)	(28.8)	(21.6)
Other income	0.1	0.0	0.1	0.1
Adjusted EBITDA	5.2	(2.8)	128.5	99.1
Online Wagering
Segment Reporting Information [Line Items]
Net revenue	70.4	72.1	229.8	229.8
Taxes and purses	(4.4)	(4.2)	(12.0)	(12.2)
Marketing and advertising	(3.6)	(0.6)	(9.1)	(4.5)
Salaries and benefits	(3.0)	(2.1)	(8.2)	(6.6)
Content Expense	(36.5)	(37.3)	(120.4)	(119.3)
Adjusted EBITDA Selling, General & Administrative Expenses	(1.8)	(1.4)	(5.5)	(4.4)
Other Cost and Expense, Operating	(6.1)	(5.7)	(20.5)	(19.7)
Other income	0.0	0.0	0.0
Adjusted EBITDA	15.0	20.8	54.1	63.1
Gaming
Segment Reporting Information [Line Items]
Net revenue	178.6	110.5	526.5	331.2
Taxes and purses	(71.2)	(37.9)	(204.7)	(111.4)
Marketing and advertising	(5.5)	(3.6)	(15.7)	(10.7)
Salaries and benefits	(26.6)	(16.8)	(76.5)	(49.3)
Content Expense	(1.6)	(0.9)	(4.5)	(2.9)
Adjusted EBITDA Selling, General & Administrative Expenses	(7.9)	(4.5)	(21.2)	(12.3)
Other Cost and Expense, Operating	(21.2)	(14.8)	(62.0)	(44.2)
Other income	27.1	12.7	70.7	36.4
Adjusted EBITDA	$ 71.7	$ 44.7	$ 212.6	$ 136.8