Segment Information - Information About Reported Segments (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($) Segments	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)
Segment Reporting Information [Line Items]
Racing	$ 38.5	$ 38.8	$ 220.8	$ 218.0
Casinos	83.0	82.7	253.9	252.5
TwinSpires	54.7	50.4	172.3	156.5
Big Fish Games	122.3	103.6	369.6	300.0
Other Investments	4.5	4.0	12.9	12.1
Corporate	$ 0.4	0.3	0.8	0.8
Number of Operating Segments | Segments	6
Property, Plant and Equipment, Additions			44.1	30.8
Net revenue from external customers	$ 303.4	279.8	1,030.3	939.9
Intercompany net revenues	0.0	0.0	0.0	0.0
Total segment Adjusted EBITDA	67.3	72.2	283.0	280.9
Adjusted Corporate EBITDA	(2.0)	(1.6)	(5.9)	(5.2)
Change in Big Fish Games deferred revenue	3.8	(10.9)	(5.0)	(32.0)
Stock-based compensation expense	(4.9)	(4.5)	(14.3)	(10.6)
Other charges	(3.1)	0.0	(3.4)	0.0
Equity investments - interest, depreciation and amortization expense	(2.5)	(2.2)	(7.5)	(6.4)
Other (charges) and recoveries, net	0.0	(0.1)	(0.4)	6.0
Big Fish Games acquisition expense	(1.1)	(2.8)	(4.9)	(17.4)
Calder exit costs	(0.5)	(12.7)	(2.4)	(13.5)
Depreciation and amortization	(27.5)	(27.4)	(81.4)	(82.1)
Interest (expense) income, net	(11.1)	(6.7)	(32.8)	(21.1)
Income before income tax provision	20.4	4.9	130.9	103.8
Income tax provision	(11.7)	(0.7)	(49.6)	(46.1)
Net income	8.7	4.2	81.3	57.7
Foreign currency translation, net of tax	0.0	0.0	0.2	(0.4)
Comprehensive income	8.7	4.2	81.5	57.3
Racing Segment [Member]
Segment Reporting Information [Line Items]
Racing	38.5	38.8	220.8	218.0
Property, Plant and Equipment, Additions			23.4	8.3
Net revenue from external customers	41.3	41.2	234.5	229.3
Intercompany net revenues	2.8	2.4	13.7	11.3
Total segment Adjusted EBITDA	0.4	0.3	84.3	76.3
Racing Segment [Member] | Churchill Downs
Segment Reporting Information [Line Items]
Racing	8.7	7.9	140.1	136.7
Intercompany net revenues	0.9	0.7	8.2	6.3
Racing Segment [Member] | Arlington Park
Segment Reporting Information [Line Items]
Racing	24.0	25.0	49.8	48.9
Intercompany net revenues	1.9	1.7	4.5	4.1
Racing Segment [Member] | Fair Grounds
Segment Reporting Information [Line Items]
Racing	5.1	5.3	28.9	30.4
Intercompany net revenues	0.0	0.0	1.0	0.9
Racing Segment [Member] | Calder
Segment Reporting Information [Line Items]
Racing	0.7	0.6	2.0	2.0
Casino Segment [Member]
Segment Reporting Information [Line Items]
Casinos	83.0	82.7	253.9	252.5
Property, Plant and Equipment, Additions			9.7	15.4
Net revenue from external customers	83.0	82.7	253.9	252.5
Total segment Adjusted EBITDA	30.4	26.7	98.0	86.6
Casino Segment [Member] | Oxford Casino
Segment Reporting Information [Line Items]
Casinos	24.4	22.3	65.4	60.8
Casino Segment [Member] | Riverwalk Casino
Segment Reporting Information [Line Items]
Casinos	10.6	12.0	35.7	37.7
Casino Segment [Member] | Harlows Casino
Segment Reporting Information [Line Items]
Casinos	11.7	11.8	36.6	37.5
Casino Segment [Member] | Calder Casinos
Segment Reporting Information [Line Items]
Casinos	19.0	18.5	59.8	58.7
Casino Segment [Member] | Fair Grounds Slots
Segment Reporting Information [Line Items]
Casinos	8.5	8.8	27.9	29.9
Casino Segment [Member] | VSI
Segment Reporting Information [Line Items]
Casinos	8.6	9.0	27.9	27.6
Casino Segment [Member] | Saratoga Casino Holdings, LLC [Member]
Segment Reporting Information [Line Items]
Casinos	0.2	0.3	0.6	0.3
TwinSpires [Member]
Segment Reporting Information [Line Items]
TwinSpires	54.7	50.4	172.3	156.5
Property, Plant and Equipment, Additions			5.4	3.1
Net revenue from external customers	55.1	50.7	173.3	157.3
Intercompany net revenues	0.4	0.3	1.0	0.8
Total segment Adjusted EBITDA	14.3	13.1	44.8	39.3
Big Fish Games [Member]
Segment Reporting Information [Line Items]
Big Fish Games	122.3	103.6	369.6	300.0
Property, Plant and Equipment, Additions			3.6	3.0
Net revenue from external customers	122.3	103.6	369.6	300.0
Total segment Adjusted EBITDA	23.4	33.2	58.9	81.5
Other Investments Segment [Member]
Segment Reporting Information [Line Items]
Other Investments	4.5	4.0	12.9	12.1
Property, Plant and Equipment, Additions			0.8	0.4
Intercompany net revenues	0.7	0.8	3.0	2.7
Total segment Adjusted EBITDA	0.8	0.5	2.9	2.4
Corporate
Segment Reporting Information [Line Items]
Corporate	0.4	0.3	0.8	0.8
Property, Plant and Equipment, Additions			1.2	0.6
Net revenue from external customers	0.4	0.3	0.8	0.8
Total segment Adjusted EBITDA	(2.0)	(1.6)	(5.9)	(5.2)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intercompany net revenues	(3.9)	(3.5)	(17.7)	(14.8)
Social casino | Big Fish Games [Member]
Segment Reporting Information [Line Items]
Big Fish Games	44.3	47.4	138.3	145.4
Casual and mid-core free-to-play | Big Fish Games [Member]
Segment Reporting Information [Line Items]
Big Fish Games	56.1	32.6	162.5	86.5
Premium | Big Fish Games [Member]
Segment Reporting Information [Line Items]
Big Fish Games	23.7	27.3	75.0	85.6
Fair value adjustments | Big Fish Games [Member]
Segment Reporting Information [Line Items]
Big Fish Games	$ (1.8)	$ (3.7)	$ (6.2)	$ (17.5)