Segment Information Adjusted EBITDA by Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Net revenue from external customers	$ 314.8	$ 303.4	$ 1,046.2	$ 1,030.3
Research & development	(9.7)	(8.8)	(29.9)	(29.3)
Adjusted EBITDA	76.0	71.1	306.3	278.0
Racing Segment [Member]
Segment Reporting Information [Line Items]
Net revenue from external customers	41.9	41.3	243.7	234.5
Taxes & purses	(11.2)	(11.2)	(54.3)	(52.7)
Platform & development fees	0.0	0.0	0.0	0.0
Marketing & advertising	(1.0)	(1.1)	(3.9)	(3.8)
Salaries & benefits	(10.3)	(10.3)	(32.4)	(31.4)
Content expense	(3.8)	(3.9)	(11.7)	(12.0)
SG&A expense	(3.9)	(4.0)	(11.9)	(11.9)
Research & development	0.0	0.0	0.0	0.0
Other operating expense	10.1	10.5	39.4	38.8
Other income (expense)	0.1	0.1	0.6	0.4
Adjusted EBITDA	1.7	0.4	90.7	84.3
Casino Segment [Member]
Segment Reporting Information [Line Items]
Net revenue from external customers	87.5	83.0	263.3	253.9
Taxes & purses	(28.9)	(28.1)	(87.7)	(84.6)
Platform & development fees	0.0	0.0	0.0	0.0
Marketing & advertising	(3.1)	(3.0)	(9.1)	(9.5)
Salaries & benefits	(13.5)	(13.4)	(40.0)	(38.2)
Content expense	0.0	0.0	0.0	0.0
SG&A expense	(5.5)	(5.4)	(16.3)	(15.8)
Research & development	0.0	0.0	0.0	0.0
Other operating expense	9.8	10.0	31.0	29.4
Other income (expense)	12.8	7.3	33.1	21.6
Adjusted EBITDA	39.5	30.4	112.3	98.0
TwinSpires [Member]
Segment Reporting Information [Line Items]
Net revenue from external customers	66.1	55.5	199.2	174.1
Taxes & purses	(4.5)	(4.0)	(11.6)	(8.8)
Platform & development fees	0.0	0.0	0.0	0.0
Marketing & advertising	(1.1)	(1.0)	(6.7)	(5.2)
Salaries & benefits	(2.3)	(2.3)	(7.1)	(6.9)
Content expense	(30.9)	(26.0)	(96.5)	(83.4)
SG&A expense	(3.2)	(3.0)	(8.9)	(8.6)
Research & development	0.0	0.0	0.0	0.0
Other operating expense	5.3	4.5	17.1	15.6
Other income (expense)	0.0	0.0	0.0	0.0
Adjusted EBITDA	18.8	14.7	51.3	45.6
Big Fish Games [Member]
Segment Reporting Information [Line Items]
Net revenue from external customers	117.9	122.3	342.5	369.6
Taxes & purses	0.0	0.0	0.0	0.0
Platform & development fees	(42.1)	(45.2)	(124.0)	(135.2)
Marketing & advertising	(31.8)	(26.3)	(84.3)	(106.2)
Salaries & benefits	(6.8)	(6.2)	(20.7)	(18.4)
Content expense	0.0	0.0	0.0	0.0
SG&A expense	(5.3)	(4.4)	(15.1)	(13.6)
Research & development	(9.7)	(8.8)	(29.9)	(29.3)
Other operating expense	4.0	3.9	11.3	11.8
Other income (expense)	(1.2)	(0.3)	(1.6)	(1.2)
Adjusted EBITDA	17.0	27.2	55.6	53.9
Other Segments [Member]
Segment Reporting Information [Line Items]
Net revenue from external customers	5.7	5.2	17.7	15.9
Taxes & purses	0.0	0.0	0.0	0.0
Platform & development fees	0.0	0.0	0.0	0.0
Marketing & advertising	0.0	0.0	0.0	0.0
Salaries & benefits	(2.9)	(2.7)	(9.1)	(8.2)
Content expense	0.0	0.0	0.0	0.0
SG&A expense	(0.8)	(0.9)	(2.3)	(2.5)
Research & development	0.0	0.0	0.0	0.0
Other operating expense	1.1	0.9	3.6	2.6
Other income (expense)	0.2	0.1	0.3	0.3
Adjusted EBITDA	1.1	0.8	3.0	2.9
Corporate
Segment Reporting Information [Line Items]
Net revenue from external customers	0.0	0.0	0.0	0.0
Taxes & purses	0.0	0.0	0.0	0.0
Platform & development fees	0.0	0.0	0.0	0.0
Marketing & advertising	0.0	0.0	0.0	0.0
Salaries & benefits	0.0	0.0	0.0	0.0
Content expense	0.0	0.0	0.0	0.0
SG&A expense	(2.2)	(2.2)	(6.2)	(6.2)
Research & development	0.0	0.0	0.0	0.0
Other operating expense	(0.1)	0.2	0.4	0.5
Other income (expense)	0.0	0.0	0.0	0.0
Adjusted EBITDA	$ (2.1)	$ (2.4)	$ (6.6)	$ (6.7)