Segment Information Adjusted EBITDA by Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Net revenue from external customers	$ 303.4	$ 279.8	$ 1,030.3	$ 939.9
Research & development	(8.8)	(9.9)	(29.3)	(30.0)
Total segment Adjusted EBITDA	67.3	72.2	283.0	280.9
Racing Segment [Member]
Segment Reporting Information [Line Items]
Net revenue from external customers	41.3	41.2	234.5	229.3
Taxes & purses	(11.2)	(11.2)	(52.7)	(52.3)
Platform & development fees	0.0	0.0	0.0	0.0
Marketing & advertising	(1.1)	(1.1)	(3.8)	(5.4)
Salaries & benefits	(10.3)	(9.5)	(31.4)	(30.3)
Content expense	(3.9)	(3.6)	(12.0)	(11.3)
SG&A expense	(4.0)	(4.3)	(11.9)	(13.0)
Research & development	0.0	0.0	0.0	0.0
Other Cost and Expense, Operating	10.5	11.4	38.8	41.2
Other income (expense)	0.1	0.2	0.4	0.5
Total segment Adjusted EBITDA	0.4	0.3	84.3	76.3
Casino Segment [Member]
Segment Reporting Information [Line Items]
Net revenue from external customers	83.0	82.7	253.9	252.5
Taxes & purses	(28.1)	(27.5)	(84.6)	(83.4)
Platform & development fees	0.0	0.0	0.0	0.0
Marketing & advertising	(3.0)	(3.2)	(9.5)	(9.4)
Salaries & benefits	(13.4)	(12.8)	(38.2)	(38.2)
Content expense	0.0	0.0	0.0	0.0
SG&A expense	(5.4)	(6.9)	(15.8)	(17.9)
Research & development	0.0	0.0	0.0	0.0
Other Cost and Expense, Operating	10.0	10.0	29.4	31.3
Other income (expense)	7.3	4.4	21.6	14.3
Total segment Adjusted EBITDA	30.4	26.7	98.0	86.6
TwinSpires [Member]
Segment Reporting Information [Line Items]
Net revenue from external customers	55.1	50.7	173.3	157.3
Taxes & purses	(4.0)	(3.6)	(8.8)	(8.2)
Platform & development fees	0.0	0.0	0.0	0.0
Marketing & advertising	(1.0)	(0.7)	(5.2)	(3.7)
Salaries & benefits	(2.3)	(2.6)	(6.9)	(7.5)
Content expense	(26.0)	(23.6)	(83.4)	(75.9)
SG&A expense	(3.0)	(3.1)	(8.6)	(8.6)
Research & development	0.0	0.0	0.0	0.0
Other Cost and Expense, Operating	4.5	4.2	15.6	14.1
Other income (expense)	0.0	0.2	0.0	0.0
Total segment Adjusted EBITDA	14.3	13.1	44.8	39.3
Big Fish Games [Member]
Segment Reporting Information [Line Items]
Net revenue from external customers	122.3	103.6	369.6	300.0
Taxes & purses	0.0	0.0	0.0	0.0
Platform & development fees	(45.2)	(36.1)	(135.2)	(103.0)
Marketing & advertising	(26.3)	(21.9)	(106.2)	(76.7)
Salaries & benefits	(6.2)	(5.4)	(18.4)	(16.5)
Content expense	0.0	0.0	0.0	0.0
SG&A expense	(4.4)	(3.8)	(13.6)	(12.6)
Research & development	(8.8)	(9.9)	(29.3)	(30.0)
Other Cost and Expense, Operating	3.9	3.9	11.8	10.9
Other income (expense)	(0.3)	(0.3)	(1.2)	(0.8)
Change in deferred revenue(1)	(3.8)	10.9	5.0	32.0
Total segment Adjusted EBITDA	23.4	33.2	58.9	81.5
Other Segments [Member]
Segment Reporting Information [Line Items]
Net revenue from external customers	5.2	4.8	15.9	14.8
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	(2.7)	(2.8)	(8.2)	(8.3)
Content expense	0.0	0.0	0.0	0.0
SG&A expense	(0.9)	(0.7)	(2.5)	(1.8)
Research & development	0.0	0.0	0.0	0.0
Other Cost and Expense, Operating	0.9	0.8	2.6	2.4
Other income (expense)	0.1	0.0	0.3	0.1
Total segment Adjusted EBITDA	0.8	0.5	2.9	2.4
Corporate
Segment Reporting Information [Line Items]
Net revenue from external customers	0.4	0.3	0.8	0.8
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)	(1.7)	(6.2)	(4.5)
Research & development	0.0	0.0	0.0	0.0
Other Cost and Expense, Operating	0.2	0.2	0.5	1.5
Other income (expense)	0.0	0.0	0.0	0.0
Total segment Adjusted EBITDA	$ (2.0)	$ (1.6)	$ (5.9)	$ (5.2)