Segment Information - Information About Reported Segments (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($) Segments	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)
Segment Reporting Information [Line Items]
Racing	$ 182,500,000	$ 165,300,000	$ 206,200,000	$ 189,200,000
TwinSpires	93,700,000	80,500,000	156,900,000	132,500,000
Casino	98,200,000	88,300,000	196,300,000	175,800,000
Other Investments	5,000,000	5,200,000	9,300,000	9,300,000
Adjusted EBITDA	$ 174,500,000	154,000,000	223,700,000	190,300,000
Number of Operating Segments | Segments	5
Property, Plant and Equipment, Additions			72,200,000	64,000,000
Intercompany net revenues	$ 0	0	0	0
Comprehensive income	102,900,000	78,000,000	284,900,000	85,200,000
Foreign currency translation, net of tax	0	300,000	0	400,000
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Noncontrolling Interest	(200,000)	0	(200,000)	0
Net income	103,100,000	78,300,000	285,100,000	85,600,000
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	100,000	(5,600,000)	(167,800,000)	(10,700,000)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	103,200,000	72,700,000	117,300,000	74,900,000
Depreciation and amortization	15,300,000	14,400,000	29,100,000	49,300,000
Interest expense	9,700,000	11,600,000
Income tax (provision) benefit	32,800,000	47,000,000	35,400,000	47,600,000
Earnings Before Interest Taxes Depreciation and Amortization	161,000,000	145,700,000
Stock-based compensation	6,400,000	4,400,000	12,600,000	11,700,000
Pre-Opening Costs	700,000	300,000
Other income, expense:	0	200,000
Interest, depreciation and amortization expense related to equity investments	4,300,000	3,100,000
Transaction expense, net	2,100,000	500,000	3,500,000	500,000
Calder exit costs	0	200,000	0	600,000
Total adjustments to EBITDA	13,500,000	8,300,000	22,600,000	15,800,000
Adjusted EBITDA	174,500,000	154,000,000	223,700,000	190,300,000
Racing Segment [Member]
Segment Reporting Information [Line Items]
Racing	182,500,000	165,300,000	206,200,000	189,200,000
Adjusted EBITDA	109,100,000	98,700,000	99,700,000	89,000,000
Property, Plant and Equipment, Additions			43,000,000	38,400,000
Intercompany net revenues	11,600,000	10,400,000	14,100,000	12,600,000
Racing Segment [Member] | Churchill Downs
Segment Reporting Information [Line Items]
Racing	154,900,000	136,700,000	156,900,000	139,000,000
Intercompany net revenues	9,400,000	8,400,000	9,700,000	8,700,000
Racing Segment [Member] | Arlington Park
Segment Reporting Information [Line Items]
Racing	17,700,000	18,000,000	26,000,000	26,500,000
Intercompany net revenues	2,100,000	1,900,000	3,300,000	2,900,000
Racing Segment [Member] | Fair Grounds
Segment Reporting Information [Line Items]
Racing	9,200,000	10,000,000	22,000,000	22,500,000
Intercompany net revenues	100,000	100,000	1,100,000	1,000,000
Racing Segment [Member] | Calder
Segment Reporting Information [Line Items]
Racing	700,000	600,000	1,300,000	1,200,000
Casino Segment [Member]
Segment Reporting Information [Line Items]
Casino	98,200,000	88,300,000	196,300,000	175,800,000
Adjusted EBITDA	43,900,000	37,500,000	88,200,000	72,800,000
Property, Plant and Equipment, Additions			5,900,000	15,600,000
Casino Segment [Member] | Oxford Casino
Segment Reporting Information [Line Items]
Casino	26,200,000	23,100,000	50,400,000	44,000,000
Casino Segment [Member] | Riverwalk Casino
Segment Reporting Information [Line Items]
Casino	13,600,000	12,000,000	28,000,000	23,500,000
Casino Segment [Member] | Harlows Casino
Segment Reporting Information [Line Items]
Casino	12,500,000	12,500,000	25,800,000	26,000,000
Casino Segment [Member] | Calder Casinos
Segment Reporting Information [Line Items]
Casino	25,300,000	21,800,000	49,600,000	43,200,000
Casino Segment [Member] | Fair Grounds Slots
Segment Reporting Information [Line Items]
Casino	9,200,000	8,800,000	19,800,000	19,000,000
Casino Segment [Member] | VSI
Segment Reporting Information [Line Items]
Casino	11,100,000	9,800,000	22,100,000	19,500,000
Casino Segment [Member] | Saratoga Casino Holdings, LLC [Member]
Segment Reporting Information [Line Items]
Casino	300,000	300,000	600,000	600,000
TwinSpires [Member]
Segment Reporting Information [Line Items]
TwinSpires	93,700,000	80,500,000	156,900,000	132,500,000
Adjusted EBITDA	23,100,000	19,300,000	39,600,000	32,500,000
Property, Plant and Equipment, Additions			4,700,000	5,200,000
Intercompany net revenues	400,000	300,000	800,000	600,000
Other Investments Segment [Member]
Segment Reporting Information [Line Items]
Other Investments	5,000,000	5,200,000	9,300,000	9,300,000
Property, Plant and Equipment, Additions			17,600,000	700,000
Intercompany net revenues	1,500,000	1,300,000	2,700,000	2,700,000
Corporate
Segment Reporting Information [Line Items]
Adjusted EBITDA	(2,700,000)	(2,800,000)	(5,200,000)	(5,900,000)
Property, Plant and Equipment, Additions			1,000,000	600,000
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intercompany net revenues	(13,500,000)	(12,000,000)	(17,600,000)	(15,900,000)
Saratoga Harness Racing Inc Joint Venture [Member]
Segment Reporting Information [Line Items]
Adjusted Corporate EBITDA	(2,700,000.0)	(2,800,000.0)	(5,200,000.0)	(5,900,000.0)
Saratoga Harness Racing Inc Joint Venture [Member] | Racing Segment [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	109,100,000.0	98,700,000.0	99,700,000.0	89,000,000
Saratoga Harness Racing Inc Joint Venture [Member] | Casino Segment [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	43,900,000.0	37,500,000.0	88,200,000.0	72,800,000.0
Saratoga Harness Racing Inc Joint Venture [Member] | TwinSpires [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	23,100,000.0	19,300,000.0	39,600,000.0	32,500,000.0
Saratoga Harness Racing Inc Joint Venture [Member] | Other Investments Segment [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	1,100,000.0	1,300,000.0	1,400,000.0	1,900,000.0
Continuing Operations [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization			29,100,000	28,600,000
Interest expense			19,300,000	23,400,000
Income tax (provision) benefit			35,400,000	47,600,000
Earnings Before Interest Taxes Depreciation and Amortization			201,100,000	174,500,000
Stock-based compensation	$ 6,400,000	$ 4,400,000	9,200,000	7,800,000
Pre-Opening Costs			1,300,000	300,000
Other income, expense:			0	0
Interest, depreciation and amortization expense related to equity investments			8,600,000	6,600,000
Transaction expense, net			3,500,000	500,000
Calder exit costs			$ 0	$ 600,000