Segment Information - Total Asset Information For Segments (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 2,224.7		$ 2,277.4
Capital expenditures	44.1	$ 30.8
Racing Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	424.4		437.1
Capital expenditures	23.4	8.3
Casino Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	621.8		631.3
Capital expenditures	9.7	15.4
TwinSpires [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	208.1		202.4
Capital expenditures	5.4	3.1
Big Fish Games [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	923.0		947.1
Capital expenditures	3.6	3.0
Other Investments Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	10.9		12.2
Capital expenditures	0.8	0.4
Corporate
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	36.5		$ 47.3
Capital expenditures	$ 1.2	$ 0.6