Segment Information - Information About Reported Segments (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($) Segments	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)
Segment Reporting Information [Line Items]
Racing	$ 38,800,000	$ 38,500,000	$ 228,000,000	$ 220,800,000
Casinos	87,500,000	83,000,000	263,300,000	253,900,000
TwinSpires	65,900,000	55,100,000	198,400,000	173,100,000
Big Fish Games	117,900,000	122,300,000	342,500,000	369,600,000
Other Investments	$ 4,700,000	4,500,000	14,000,000	12,900,000
Number of Operating Segments | Segments	6
Property, Plant and Equipment, Additions			89,100,000	44,100,000
Intercompany net revenues	$ 0	0	0	0
Adjusted EBITDA	76,000,000	71,100,000	306,300,000	278,000,000
Stock-based compensation	5,800,000	4,900,000	17,500,000	14,300,000
Other income, expense:	(400,000)	(3,100,000)	(500,000)	(3,400,000)
Interest, depreciation and amortization expense related to equity investments	4,000,000	2,500,000	10,600,000	7,500,000
Other charges and recoveries, net	0	0	0	400,000
Acquisition expense, net	700,000	1,100,000	1,700,000	4,900,000
Calder exit costs	200,000	500,000	800,000	2,400,000
Total adjustments to EBITDA	11,100,000	12,100,000	31,100,000	32,900,000
Adjusted Earnings Before Interest, Tax, Depreciation, and Amortization	76,000,000	71,100,000	306,300,000	278,000,000
Total adjustments to EBITDA	24,000,000	27,500,000	73,300,000	81,400,000
Adjusted EBITDA	12,600,000	11,100,000	36,000,000	32,800,000
Income (loss) from operations before provision for income taxes	28,300,000	20,400,000	165,900,000	130,900,000
Income tax (provision) benefit	11,600,000	11,700,000	63,600,000	49,600,000
Earnings Before Interest Taxes Depreciation and Amortization	64,900,000	59,000,000	275,200,000	245,100,000
Net income	16,700,000	8,700,000	102,300,000	81,300,000
Foreign currency translation, net of tax	(500,000)	0	(100,000)	(200,000)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Noncontrolling Interest	(100,000)	0	(100,000)	0
Comprehensive income	17,300,000	8,700,000	102,500,000	81,500,000
Racing Segment [Member]
Segment Reporting Information [Line Items]
Racing	38,800,000	38,500,000	228,000,000	220,800,000
Property, Plant and Equipment, Additions			47,800,000	23,400,000
Intercompany net revenues	3,100,000	2,800,000	15,700,000	13,700,000
Adjusted EBITDA	1,700,000	400,000	90,700,000	84,300,000
Racing Segment [Member] | Churchill Downs
Segment Reporting Information [Line Items]
Racing	8,100,000	8,700,000	147,100,000	140,100,000
Intercompany net revenues	900,000	900,000	9,600,000	8,200,000
Racing Segment [Member] | Arlington Park
Segment Reporting Information [Line Items]
Racing	25,000,000	24,000,000	51,500,000	49,800,000
Intercompany net revenues	2,200,000	1,900,000	5,100,000	4,500,000
Racing Segment [Member] | Fair Grounds
Segment Reporting Information [Line Items]
Racing	5,000,000	5,100,000	27,500,000	28,900,000
Intercompany net revenues	0	0	1,000,000	1,000,000
Racing Segment [Member] | Calder
Segment Reporting Information [Line Items]
Racing	700,000	700,000	1,900,000	2,000,000
Casino Segment [Member]
Segment Reporting Information [Line Items]
Casinos	87,500,000	83,000,000	263,300,000	253,900,000
Property, Plant and Equipment, Additions			26,000,000	9,700,000
Adjusted EBITDA	39,500,000	30,400,000	112,300,000	98,000,000
Casino Segment [Member] | Oxford Casino
Segment Reporting Information [Line Items]
Casinos	25,200,000	24,400,000	69,200,000	65,400,000
Casino Segment [Member] | Riverwalk Casino
Segment Reporting Information [Line Items]
Casinos	12,200,000	10,600,000	35,700,000	35,700,000
Casino Segment [Member] | Harlows Casino
Segment Reporting Information [Line Items]
Casinos	12,300,000	11,700,000	38,300,000	36,600,000
Casino Segment [Member] | Calder Casinos
Segment Reporting Information [Line Items]
Casinos	19,400,000	19,000,000	62,600,000	59,800,000
Casino Segment [Member] | Fair Grounds Slots
Segment Reporting Information [Line Items]
Casinos	8,700,000	8,500,000	27,700,000	27,900,000
Casino Segment [Member] | VSI
Segment Reporting Information [Line Items]
Casinos	9,300,000	8,600,000	28,800,000	27,900,000
Casino Segment [Member] | Saratoga Casino Holdings, LLC [Member]
Segment Reporting Information [Line Items]
Casinos	400,000	200,000	1,000,000	600,000
TwinSpires [Member]
Segment Reporting Information [Line Items]
TwinSpires	65,900,000	55,100,000	198,400,000	173,100,000
Property, Plant and Equipment, Additions			7,300,000	5,400,000
Intercompany net revenues	200,000	400,000	800,000	1,000,000
Adjusted EBITDA	18,800,000	14,700,000	51,300,000	45,600,000
Big Fish Games [Member]
Segment Reporting Information [Line Items]
Big Fish Games	117,900,000	122,300,000	342,500,000	369,600,000
Property, Plant and Equipment, Additions			5,600,000	3,600,000
Adjusted EBITDA	17,000,000	27,200,000	55,600,000	53,900,000
Other Investments Segment [Member]
Segment Reporting Information [Line Items]
Other Investments	4,700,000	4,500,000	14,000,000	12,900,000
Property, Plant and Equipment, Additions			1,300,000	800,000
Intercompany net revenues	1,000,000	700,000	3,700,000	3,000,000
Corporate
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Additions			1,100,000	1,200,000
Adjusted EBITDA	(2,100,000)	(2,400,000)	(6,600,000)	(6,700,000)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intercompany net revenues	(4,300,000)	(3,900,000)	(20,200,000)	(17,700,000)
Social casino | Big Fish Games [Member]
Segment Reporting Information [Line Items]
Big Fish Games	53,400,000	44,300,000	149,100,000	138,300,000
Casual and mid-core free-to-play | Big Fish Games [Member]
Segment Reporting Information [Line Items]
Big Fish Games	46,100,000	56,100,000	135,300,000	162,500,000
Premium | Big Fish Games [Member]
Segment Reporting Information [Line Items]
Big Fish Games	18,400,000	21,900,000	58,100,000	68,800,000
Saratoga Harness Racing Inc Joint Venture [Member]
Segment Reporting Information [Line Items]
Adjusted Corporate EBITDA	(2,100,000.0)	(2,400,000.0)	(6,600,000.0)	(6,700,000.0)
Saratoga Harness Racing Inc Joint Venture [Member] | Racing Segment [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	1,700,000.0	400,000.0	90,700,000.0	84,300,000.0
Saratoga Harness Racing Inc Joint Venture [Member] | Casino Segment [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	39,500,000.0	30,400,000.0	112,300,000.0	98,000,000
Saratoga Harness Racing Inc Joint Venture [Member] | TwinSpires [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	18,800,000.0	14,700,000.0	51,300,000.0	45,600,000.0
Saratoga Harness Racing Inc Joint Venture [Member] | Big Fish Games [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	17,000,000	27,200,000.0	55,600,000.0	53,900,000.0
Saratoga Harness Racing Inc Joint Venture [Member] | Other Investments Segment [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 1,100,000.0	$ 800,000.0	$ 3,000,000	$ 2,900,000.0