Segment Information Adjusted EBITDA by Segment (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Net revenue	$ 221,300,000	$ 196,900,000	$ 790,000,000	$ 703,700,000
Adjusted EBITDA	62,100,000	58,100,000	285,800,000	248,400,000
Racing Segment [Member]
Segment Reporting Information [Line Items]
Net revenue	41,000,000	41,900,000	261,300,000	243,700,000
Taxes & purses	11,000,000	11,200,000	55,700,000	54,300,000
Marketing & advertising	1,200,000	1,000,000	5,600,000	3,900,000
Salaries & benefits	10,600,000	10,300,000	34,500,000	32,400,000
Content expense	3,400,000	3,800,000	11,200,000	11,700,000
SG&A expense	4,200,000	3,900,000	12,800,000	11,900,000
Other operating expense	11,800,000	10,100,000	43,400,000	39,400,000
Other income	0	100,000	400,000	600,000
Adjusted EBITDA	(1,200,000)	1,700,000	98,500,000	90,700,000
Casino Segment [Member]
Segment Reporting Information [Line Items]
Net revenue	105,000,000	87,500,000	301,300,000	263,300,000
Taxes & purses	36,000,000	28,900,000	101,800,000	87,700,000
Marketing & advertising	3,400,000	3,100,000	10,100,000	9,100,000
Salaries & benefits	14,600,000	13,500,000	41,700,000	40,000,000
Content expense	0	0	0	0
SG&A expense	6,200,000	5,500,000	17,200,000	16,300,000
Other operating expense	11,800,000	9,800,000	33,000,000	31,000,000
Other income	12,700,000	12,800,000	36,400,000	33,100,000
Adjusted EBITDA	45,700,000	39,500,000	133,900,000	112,300,000
TwinSpires [Member]
Segment Reporting Information [Line Items]
Net revenue	72,100,000	66,100,000	229,800,000	199,200,000
Taxes & purses	4,200,000	4,500,000	12,200,000	11,600,000
Marketing & advertising	600,000	1,100,000	4,500,000	6,700,000
Salaries & benefits	2,100,000	2,300,000	6,600,000	7,100,000
Content expense	37,300,000	30,900,000	119,300,000	96,500,000
SG&A expense	2,900,000	3,200,000	8,600,000	8,900,000
Other operating expense	5,700,000	5,300,000	19,700,000	17,100,000
Other income	0	0	0	0
Adjusted EBITDA	19,300,000	18,800,000	58,900,000	51,300,000
Other Segments [Member]
Segment Reporting Information [Line Items]
Net revenue	7,800,000	5,700,000	19,800,000	17,700,000
Taxes & purses	700,000	0	700,000	0
Marketing & advertising	100,000	0	200,000	0
Salaries & benefits	3,400,000	2,900,000	10,200,000	9,100,000
Content expense	0	0	0	0
SG&A expense	1,200,000	800,000	2,600,000	2,300,000
Other operating expense	1,300,000	1,100,000	3,700,000	3,600,000
Other income	0	200,000	100,000	300,000
Adjusted EBITDA	1,100,000	1,100,000	2,500,000	3,000,000
Corporate
Segment Reporting Information [Line Items]
Net revenue	0	0	0	0
Taxes & purses	0	0	0	0
Marketing & advertising	0	0	0	0
Salaries & benefits	0	0	0	0
Content expense	0	0	0	0
SG&A expense	2,600,000	3,100,000	7,600,000	8,500,000
Other operating expense	200,000	(100,000)	500,000	400,000
Other income	0	0	100,000	0
Adjusted EBITDA	(2,800,000)	(3,000,000)	(8,000,000)	(8,900,000)
Saratoga Harness Racing Inc Joint Venture [Member] | Racing Segment [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	(1,200,000.0)	1,700,000.0	98,500,000.0	90,700,000.0
Saratoga Harness Racing Inc Joint Venture [Member] | Casino Segment [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	45,700,000.0	39,500,000.0	133,900,000.0	112,300,000.0
Saratoga Harness Racing Inc Joint Venture [Member] | TwinSpires [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	19,300,000.0	18,800,000.0	58,900,000.0	51,300,000.0
Saratoga Harness Racing Inc Joint Venture [Member] | Other Investments Segment [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 1,100,000.0	$ 1,100,000.0	$ 2,500,000.0	$ 3,000,000.0