Segment Information - Total Asset Information For Segments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 2,256.1		$ 2,254.4
Capital expenditures	37.5	$ 16.4
Racing Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	437.1		454.6
Capital expenditures	23.6	9.4
Casino Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	655.4		628.7
Capital expenditures	8.1	3.3
TwinSpires [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	205.5		209.9
Capital expenditures	3.2	1.9
Big Fish Games [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	900.0		893.8
Capital expenditures	2.0	1.2
Other Investments Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	10.1		11.1
Capital expenditures	0.4	0.2
Corporate
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	48.0		$ 56.3
Capital expenditures	$ 0.2	$ 0.4