Segment Information - Total Asset Information For Segments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 2,238.3		$ 2,277.4
Capital expenditures	16.4	$ 9.8
Racing Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	416.8		437.1
Capital expenditures	9.4	3.3
Casino Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	625.9		631.3
Capital expenditures	3.3	3.6
TwinSpires [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	204.6		202.4
Capital expenditures	1.9	1.6
Big Fish Games [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	946.7		947.1
Capital expenditures	1.2	1.2
Other Investments Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	10.4		12.2
Capital expenditures	0.2	0.1
Corporate
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	33.9		$ 47.3
Capital expenditures	$ 0.4	$ 0.0