Segment Information - Schedule of Adjusted EBITDA by Segment (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net revenue	$ 278.3	$ 303.4	$ 438.5	$ 288.4	$ 272.4	$ 279.8	$ 409.2	$ 250.9	$ 1,308.6	$ 1,212.3	$ 812.2
Research & development									(39.0)	(39.4)	0.0
Adjusted EBITDA									334.5	302.5	204.1
Racing
Segment Reporting Information [Line Items]
Net revenue									251.1	248.0	261.4
Taxes & purses									(64.2)	(63.6)	(72.7)
Platform & development fees									0.0	0.0	0.0
Marketing & advertising									(4.6)	(6.1)	(6.1)
Salaries & benefits									(40.9)	(39.2)	(45.1)
Content expense									(15.6)	(14.6)	(19.0)
SG&A expense									(16.2)	(16.6)	(18.4)
Research & development									0.0	0.0	0.0
Other operating expense									(47.4)	(50.9)	(54.1)
Other income (expense)									0.5	0.6	0.6
Adjusted EBITDA									79.7	71.8	61.2
Casinos
Segment Reporting Information [Line Items]
Net revenue									332.8	332.9	328.3
Taxes & purses									(110.9)	(109.9)	(108.0)
Platform & development fees									0.0	0.0	0.0
Marketing & advertising									(12.7)	(12.4)	(12.5)
Salaries & benefits									(50.8)	(49.7)	(49.1)
Content expense									0.0	0.0	0.0
SG&A expense									(21.2)	(24.1)	(25.5)
Research & development									0.0	0.0	0.0
Other operating expense									(39.1)	(41.3)	(43.5)
Other income (expense)									27.7	19.4	17.5
Adjusted EBITDA									125.8	114.9	107.2
TwinSpires
Segment Reporting Information [Line Items]
Net revenue									220.6	200.2	191.0
Taxes & purses									(11.7)	(10.6)	(9.2)
Platform & development fees									0.0	0.0	0.0
Marketing & advertising									(6.3)	(4.8)	(4.7)
Salaries & benefits									(9.4)	(9.9)	(11.5)
Content expense									(107.6)	(97.9)	(92.6)
SG&A expense									(11.9)	(11.5)	(13.0)
Research & development									0.0	0.0	0.0
Other operating expense									(19.8)	(18.0)	(21.2)
Other income (expense)									0.0	0.0	0.0
Adjusted EBITDA									55.2	48.6	39.8
Big Fish Games
Segment Reporting Information [Line Items]
Net revenue									486.2	413.7	13.9
Taxes & purses									0.0	0.0	0.0
Platform & development fees									(179.9)	(143.6)	(5.1)
Marketing & advertising									(127.9)	(107.7)	(5.7)
Salaries & benefits									(25.0)	(22.3)	(2.6)
Content expense									0.0	0.0	0.0
SG&A expense									(18.5)	(16.8)	(0.8)
Research & development									(39.0)	(39.4)	0.0
Other operating expense									(15.9)	(14.8)	(0.4)
Other income (expense)									(0.9)	(0.6)	0.0
Adjusted EBITDA									79.1	68.5	(0.7)
Other Investments
Segment Reporting Information [Line Items]
Net revenue									16.9	16.6	16.5
Taxes & purses									0.0	0.0	0.0
Platform & development fees									0.0	0.0	0.0
Marketing & advertising									0.0	0.0	0.0
Salaries & benefits									(10.9)	(11.1)	(11.8)
Content expense									0.0	0.0	0.0
SG&A expense									(3.4)	(2.5)	(2.8)
Research & development									0.0	0.0	0.0
Other operating expense									(4.1)	(3.8)	(4.5)
Other income (expense)									0.3	0.2	0.1
Adjusted EBITDA									2.7	2.9	1.6
Corporate
Segment Reporting Information [Line Items]
Net revenue									1.0	0.9	1.1
Taxes & purses									0.0	0.0	0.0
Platform & development fees									0.0	0.0	0.0
Marketing & advertising									0.0	0.0	0.0
Salaries & benefits									0.0	0.0	(0.2)
Content expense									0.0	0.0	0.0
SG&A expense									(8.6)	(6.3)	(5.3)
Research & development									0.0	0.0	0.0
Other operating expense									(0.6)	1.1	(0.7)
Other income (expense)									0.2	0.1	0.1
Adjusted EBITDA									(8.0)	(4.2)	(5.0)
Operating Segments | Racing
Segment Reporting Information [Line Items]
Net revenue									268.1	262.2	276.0
Operating Segments | Casinos
Segment Reporting Information [Line Items]
Net revenue									332.8	332.9	328.3
Operating Segments | TwinSpires
Segment Reporting Information [Line Items]
Net revenue									221.9	201.3	192.0
Operating Segments | Big Fish Games
Segment Reporting Information [Line Items]
Net revenue									486.2	413.7	13.9
Operating Segments | Other Investments
Segment Reporting Information [Line Items]
Net revenue									20.8	20.1	20.6
Operating Segments | Corporate
Segment Reporting Information [Line Items]
Net revenue									$ 1.0	$ 0.9	$ 1.1