Segment Information - Information About Reported Segments (Details) - USD ($)	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Net revenue	$ 185,100,000		$ 477,400,000		$ 438,000,000.0	$ 742,800,000
Intercompany net revenues	0		0		0	0
Net (loss) income and comprehensive (loss) income attributable to CDI	(118,800,000)		107,100,000		(142,200,000)	118,700,000
Net loss attributable to noncontrolling interest	0		0		(100,000)	0
Net (loss) income	(118,800,000)	$ (23,500,000)	107,100,000	$ 11,600,000	(142,300,000)	118,700,000
Loss from discontinued operations, net of tax	(95,200,000)		(1,200,000)		(96,100,000)	(1,500,000)
(Loss) income from continuing operations, net of tax	(23,600,000)		108,300,000		(46,200,000)	120,200,000
Depreciation and amortization	22,100,000		21,500,000		44,100,000	42,300,000
Interest expense	20,300,000		19,400,000		39,600,000	33,100,000
Income tax (benefit) provision	(7,900,000)		38,600,000		(19,500,000)	45,100,000
EBITDA	10,900,000		187,800,000		18,000,000.0	240,700,000
Stock-based compensation expense	6,100,000		7,400,000		10,400,000	12,100,000
Other charges	(100,000)		0		(100,000)	500,000
Pre-opening expense and other expense	1,900,000		900,000		3,600,000	2,200,000
Impairment of intangible assets	0		0		17,500,000	0
Transaction expense, net	200,000		600,000		500,000	4,100,000
Interest, depreciation and amortization expense related to equity investments	9,800,000		9,700,000		19,300,000	13,200,000
Fair Value of Interest Rate Swaps	1,300,000		7,900,000		16,200,000	12,200,000
Midwest Gaming's recapitalization and transactions costs	0		800,000		0	4,700,000
Other charges & recoveries, net	0		(100,000)		0	(100,000)
Total adjustments to EBITDA	19,200,000		27,200,000		67,400,000	48,900,000
Adjusted EBITDA	30,100,000		215,000,000.0		85,400,000	289,600,000
Churchill Downs
Segment Reporting Information [Line Items]
Net revenue	30,200,000		193,100,000		54,000,000.0	214,500,000
Adjusted Segment EBITDA	4,500,000		121,900,000		6,400,000	123,300,000
Online Wagering
Segment Reporting Information [Line Items]
Net revenue	121,600,000		96,000,000.0		189,300,000	159,400,000
Impairment of intangible assets					2,500,000
Adjusted Segment EBITDA	38,800,000		22,200,000		53,800,000	39,100,000
Gaming
Segment Reporting Information [Line Items]
Net revenue	37,300,000		177,800,000		186,400,000	347,900,000
Adjusted Segment EBITDA	(2,000,000.0)		76,100,000		47,000,000.0	140,900,000
Gaming | Presque Isle Downs & Casino
Segment Reporting Information [Line Items]
Impairment of intangible assets					12,500,000
Operating Segments
Segment Reporting Information [Line Items]
Net revenue	185,100,000		477,400,000		438,000,000.0	742,800,000
Adjusted Segment EBITDA	41,300,000		220,200,000		107,200,000	303,300,000
Operating Segments | Churchill Downs
Segment Reporting Information [Line Items]
Net revenue	23,300,000		182,200,000		46,800,000	203,200,000
Intercompany net revenues	6,900,000		10,900,000		7,200,000	11,300,000
Adjusted Segment EBITDA	4,500,000		121,900,000		6,400,000	123,300,000
Operating Segments | Churchill Downs | Churchill Downs Racetrack
Segment Reporting Information [Line Items]
Net revenue	15,600,000		161,000,000.0		17,500,000	163,300,000
Operating Segments | Churchill Downs | Derby City Gaming
Segment Reporting Information [Line Items]
Net revenue	7,700,000		21,200,000		29,300,000	39,900,000
Operating Segments | Online Wagering
Segment Reporting Information [Line Items]
Net revenue	121,200,000		95,600,000		188,500,000	158,700,000
Intercompany net revenues	400,000		400,000		800,000	700,000
Adjusted Segment EBITDA	38,800,000		22,200,000		53,800,000	39,100,000
Operating Segments | Online Wagering | TwinSpires
Segment Reporting Information [Line Items]
Net revenue	119,900,000		95,600,000		186,500,000	158,600,000
Operating Segments | Online Wagering | Online Sports Betting and iGaming
Segment Reporting Information [Line Items]
Net revenue	1,300,000		0		2,000,000.0	100,000
Operating Segments | Gaming
Segment Reporting Information [Line Items]
Net revenue	37,300,000		177,600,000		184,900,000	346,400,000
Intercompany net revenues	0		200,000		1,500,000	1,500,000
Adjusted Segment EBITDA	(2,000,000.0)		76,100,000		47,000,000.0	140,900,000
Operating Segments | Gaming | Fair Grounds and VSI
Segment Reporting Information [Line Items]
Net revenue	11,100,000		30,900,000		42,700,000	68,400,000
Operating Segments | Gaming | Presque Isle Downs & Casino
Segment Reporting Information [Line Items]
Net revenue	2,000,000.0		37,100,000		29,600,000	66,800,000
Operating Segments | Gaming | Calder
Segment Reporting Information [Line Items]
Net revenue	5,700,000		25,600,000		27,500,000	51,000,000.0
Operating Segments | Gaming | Oxford
Segment Reporting Information [Line Items]
Net revenue	100,000		26,300,000		20,200,000	50,200,000
Operating Segments | Gaming | Ocean Downs
Segment Reporting Information [Line Items]
Net revenue	3,100,000		21,900,000		17,900,000	40,300,000
Operating Segments | Gaming | Riverwalk
Segment Reporting Information [Line Items]
Net revenue	7,400,000		14,200,000		20,100,000	30,500,000
Operating Segments | Gaming | Harlow’s
Segment Reporting Information [Line Items]
Net revenue	5,600,000		13,300,000		17,300,000	28,600,000
Operating Segments | Gaming | Lady Luck Nemacolin
Segment Reporting Information [Line Items]
Net revenue	2,300,000		8,300,000		9,600,000	10,600,000
Segment Reconciling Items | All Other
Segment Reporting Information [Line Items]
Net revenue	3,300,000		22,000,000.0		17,800,000	34,500,000
Intercompany net revenues	2,900,000		3,400,000		5,900,000	5,600,000
Adjusted Segment EBITDA	(11,200,000)		(5,200,000)		(21,800,000)	(13,700,000)
Eliminations
Segment Reporting Information [Line Items]
Intercompany net revenues	$ (10,200,000)		$ (14,900,000)		$ (15,400,000)	$ (19,100,000)