Segment Information - Schedule of Adjusted EBITDA by Segment (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net revenues	$ 219.0	$ 221.3	$ 379.4	$ 189.3	$ 178.9	$ 196.9	$ 339.3	$ 167.5	$ 1,009.0	$ 882.6	$ 822.4
Adjusted EBITDA									328.8	286.2	252.3
Racing
Segment Reporting Information [Line Items]
Net revenues									274.3	257.3	251.1
Adjusted EBITDA									92.4	84.5	79.7
Online Wagering
Segment Reporting Information [Line Items]
Net revenues									290.2	255.6	221.6
Adjusted EBITDA									72.8	64.4	56.2
Casino
Segment Reporting Information [Line Items]
Net revenues									411.2	350.5	332.8
Adjusted EBITDA									169.5	146.0	125.8
Other Investments
Segment Reporting Information [Line Items]
Net revenues									33.3	19.2	16.9
Adjusted EBITDA									5.3	3.7	2.7
Corporate
Segment Reporting Information [Line Items]
Adjusted EBITDA									(11.2)	(12.4)	(12.1)
Operating Segments | Racing
Segment Reporting Information [Line Items]
Net revenues									295.4	276.6	268.1
Taxes & purses									(67.3)	(65.4)	(64.2)
Marketing & advertising									(6.5)	(4.9)	(4.6)
Salaries & benefits									(44.0)	(41.7)	(40.9)
Content expense									(14.4)	(15.2)	(15.6)
SG&A expense									(17.8)	(16.8)	(16.2)
Other operating expense									(53.6)	(48.9)	(47.4)
Other income									0.6	0.8	0.5
Adjusted EBITDA									92.4	84.5	79.7
Operating Segments | Online Wagering
Segment Reporting Information [Line Items]
Net revenues									291.5	256.7	222.9
Taxes & purses									(15.2)	(14.7)	(11.6)
Marketing & advertising									(6.0)	(8.2)	(6.3)
Salaries & benefits									(9.2)	(9.9)	(9.4)
Content expense									(152.0)	(125.0)	(107.6)
SG&A expense									(12.1)	(12.4)	(12.0)
Other operating expense									(24.2)	(22.1)	(19.8)
Other income									0.0	0.0	0.0
Adjusted EBITDA									72.8	64.4	56.2
Operating Segments | Casino
Segment Reporting Information [Line Items]
Net revenues									411.2	350.5	332.8
Taxes & purses									(139.9)	(117.0)	(110.9)
Marketing & advertising									(14.7)	(12.1)	(12.7)
Salaries & benefits									(58.5)	(53.2)	(50.8)
Content expense									(0.3)	0.0	0.0
SG&A expense									(26.1)	(22.6)	(21.2)
Other operating expense									(45.5)	(41.6)	(39.1)
Other income									43.3	42.0	27.7
Adjusted EBITDA									169.5	146.0	125.8
Operating Segments | Other Investments
Segment Reporting Information [Line Items]
Net revenues									37.8	23.7	20.8
Taxes & purses									(4.3)	0.0	0.0
Marketing & advertising									(1.0)	0.0	0.0
Salaries & benefits									(15.0)	(12.0)	(10.9)
Content expense									0.0	0.0	0.0
SG&A expense									(5.3)	(3.3)	(3.4)
Other operating expense									(7.0)	(5.1)	(4.1)
Other income									0.1	0.4	0.3
Adjusted EBITDA									5.3	3.7	2.7
Operating Segments | Corporate
Segment Reporting Information [Line Items]
Net revenues									0.0	0.0	0.0
Taxes & purses									0.0	0.0	0.0
Marketing & advertising									0.0	0.0	0.0
Salaries & benefits									0.0	0.0	0.0
Content expense									0.0	0.0	0.0
SG&A expense									(11.0)	(12.2)	(11.7)
Other operating expense									(0.4)	(0.5)	(0.6)
Other income									0.2	0.3	0.2
Adjusted EBITDA									$ (11.2)	(12.4)	(12.1)
Big Fish Games | Discontinued Operations, Held-for-sale
Segment Reporting Information [Line Items]
Adjusted EBITDA corporate and other expenses											3.1
Big Fish Games | Discontinued Operations, Held-for-sale | Corporate
Segment Reporting Information [Line Items]
Adjusted EBITDA corporate and other expenses										$ 3.6	$ 3.1