Goodwill - Schedule of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Balance, beginning of period	$ 841.7	$ 840.9
Additions		0.8
Adjustments	(9.5)
Balance, end of period	832.2	841.7
Racing
Goodwill [Roll Forward]
Balance, beginning of period	51.7	51.7
Additions		0.0
Adjustments	0.0
Balance, end of period	51.7	51.7
Casinos
Goodwill [Roll Forward]
Balance, beginning of period	117.6	117.6
Additions		0.0
Adjustments	0.0
Balance, end of period	117.6	117.6
TwinSpires
Goodwill [Roll Forward]
Balance, beginning of period	132.1	131.3
Additions		0.8
Adjustments	0.0
Balance, end of period	132.1	132.1
Big Fish Games
Goodwill [Roll Forward]
Balance, beginning of period	540.3	540.3
Additions		0.0
Adjustments	(9.5)
Balance, end of period	$ 530.8	$ 540.3