Segment Information - Information About Reported Segments (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($) Segments	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | Segments	3
Net revenue	$ 477,400,000	$ 379,400,000	$ 742,800,000	$ 568,700,000
Intercompany net revenues	0	0	0	0
Comprehensive income	107,100,000	102,900,000	118,700,000	285,300,000
Foreign currency translation, net of tax	0	0	0	(600,000)
Change in pension benefits, net of tax	0	(200,000)	0	(400,000)
Net income	107,100,000	103,100,000	118,700,000	285,100,000
Loss (income) from discontinued operations, net of tax	1,200,000	100,000	1,500,000	(167,800,000)
Income from continuing operations, net of tax	108,300,000	103,200,000	120,200,000	117,300,000
Depreciation and amortization	21,500,000	15,300,000	42,300,000	29,100,000
Interest expense	19,400,000	9,700,000	33,100,000	19,300,000
Income tax provision	38,600,000	32,800,000	45,100,000	35,400,000
EBITDA	187,800,000	161,000,000.0	240,700,000	201,100,000
Stock-based compensation expense	7,400,000	6,400,000	12,100,000	9,200,000
Other charges	0	0	(500,000)	0
Pre-opening expense	900,000	700,000	2,200,000	1,300,000
Interest, depreciation and amortization expense related to equity investments	9,700,000	4,300,000	13,200,000	8,600,000
Fair Value of Interest Rate Swaps	7,900,000	0	12,200,000	0
Midwest Gaming's recapitalization and transactions costs	800,000	0	4,700,000	0
Other charges & recoveries, net	(100,000)	0	(100,000)	0
Other	600,000	2,100,000	4,100,000	3,500,000
Total adjustments to EBITDA	27,200,000	13,500,000	48,900,000	22,600,000
Adjusted EBITDA	215,000,000.0	174,500,000	289,600,000	223,700,000
Churchill Downs
Segment Reporting Information [Line Items]
Net revenue	193,100,000	164,300,000	214,500,000	166,600,000
Adjusted Segment EBITDA	121,900,000	107,900,000	123,300,000	101,900,000
Online Wagering
Segment Reporting Information [Line Items]
Net revenue	96,000,000.0	94,100,000	159,400,000	157,700,000
Adjusted Segment EBITDA	22,200,000	24,400,000	39,100,000	42,300,000
Gaming
Segment Reporting Information [Line Items]
Net revenue	177,800,000	108,200,000	347,900,000	220,700,000
Adjusted Segment EBITDA	76,100,000	45,700,000	140,900,000	92,100,000
Operating Segments
Segment Reporting Information [Line Items]
Net revenue	477,400,000	379,400,000	742,800,000	568,700,000
Adjusted Segment EBITDA	220,200,000	178,000,000.0	303,300,000	236,300,000
Operating Segments | Churchill Downs
Segment Reporting Information [Line Items]
Net revenue	182,200,000	154,900,000	203,200,000	156,900,000
Intercompany net revenues	10,900,000	9,400,000	11,300,000	9,700,000
Adjusted Segment EBITDA	121,900,000	107,900,000	123,300,000	101,900,000
Operating Segments | Churchill Downs | Churchill Downs Racetrack
Segment Reporting Information [Line Items]
Net revenue	161,000,000.0	154,900,000	163,300,000	156,900,000
Operating Segments | Churchill Downs | Derby City Gaming
Segment Reporting Information [Line Items]
Net revenue	21,200,000	0	39,900,000	0
Operating Segments | Online Wagering
Segment Reporting Information [Line Items]
Net revenue	95,600,000	93,700,000	158,700,000	156,900,000
Intercompany net revenues	400,000	400,000	700,000	800,000
Adjusted Segment EBITDA	22,200,000	24,400,000	39,100,000	42,300,000
Operating Segments | Online Wagering | TwinSpires
Segment Reporting Information [Line Items]
Net revenue	95,600,000	93,700,000	158,600,000	156,900,000
Operating Segments | Online Wagering | Online Sports Betting and iGaming
Segment Reporting Information [Line Items]
Net revenue	0	0	100,000	0
Operating Segments | Gaming
Segment Reporting Information [Line Items]
Net revenue	177,600,000	108,100,000	346,400,000	219,600,000
Intercompany net revenues	200,000	100,000	1,500,000	1,100,000
Adjusted Segment EBITDA	76,100,000	45,700,000	140,900,000	92,100,000
Operating Segments | Gaming | Oxford
Segment Reporting Information [Line Items]
Net revenue	26,300,000	26,200,000	50,200,000	50,400,000
Operating Segments | Gaming | Calder
Segment Reporting Information [Line Items]
Net revenue	25,600,000	26,000,000.0	51,000,000.0	50,900,000
Operating Segments | Gaming | Riverwalk
Segment Reporting Information [Line Items]
Net revenue	14,200,000	13,600,000	30,500,000	28,000,000.0
Operating Segments | Gaming | Harlow’s
Segment Reporting Information [Line Items]
Net revenue	13,300,000	12,500,000	28,600,000	25,800,000
Operating Segments | Gaming | Fair Grounds and VSI
Segment Reporting Information [Line Items]
Net revenue	30,900,000	29,500,000	68,400,000	63,900,000
Operating Segments | Gaming | Ocean Downs
Segment Reporting Information [Line Items]
Net revenue	21,900,000	0	40,300,000	0
Operating Segments | Gaming | Presque Isle
Segment Reporting Information [Line Items]
Net revenue	37,100,000	0	66,800,000	0
Operating Segments | Gaming | Lady Luck Nemacolin
Segment Reporting Information [Line Items]
Net revenue	8,300,000	0	10,600,000	0
Operating Segments | Gaming | Saratoga
Segment Reporting Information [Line Items]
Net revenue	0	300,000	0	600,000
Segment Reconciling Items | All Other
Segment Reporting Information [Line Items]
Net revenue	22,000,000.0	22,700,000	34,500,000	35,300,000
Intercompany net revenues	3,400,000	3,600,000	5,600,000	6,000,000.0
Adjusted Segment EBITDA	(5,200,000)	(3,500,000)	(13,700,000)	(12,600,000)
Eliminations
Segment Reporting Information [Line Items]
Intercompany net revenues	$ (14,900,000)	$ (13,500,000)	$ (19,100,000)	$ (17,600,000)