Segment Information - Schedule of Total Assets and Capital Expenditures by Operating Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 2,551.0	$ 1,725.2
Capital expenditures	131.2	149.4	$ 109.0
Churchill Downs
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	31.4	109.6	54.1
Churchill Downs | Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	370.3	359.6
Online Wagering
Segment Reporting, Asset Reconciling Item [Line Items]
Capital expenditures	9.7	9.7	9.0
Online Wagering | Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	241.5	222.8
Gaming
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,030.1	877.1
Capital expenditures	37.1	20.7	39.7
Total Segments | Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,641.9	1,459.5
Capital expenditures	78.2	140.0	102.8
All Other | All Other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	909.1	265.7
Capital expenditures	$ 53.0	$ 9.4	$ 6.2