Segment Information - Total Asset Information For Segments (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 2,248.1		$ 2,277.4
Capital expenditures	34.5	$ 22.7
Racing Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	434.4		437.1
Capital expenditures	20.8	6.6
Casino Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	624.7		631.3
Capital expenditures	6.8	11.4
TwinSpires [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	211.2		202.4
Capital expenditures	3.7	2.0
Big Fish Games [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	930.0		947.1
Capital expenditures	2.2	1.9
Other Investments Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	10.5		12.2
Capital expenditures	0.4	0.3
Corporate
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	37.3		$ 47.3
Capital expenditures	$ 0.6	$ 0.5