Segment Information - Reconciliation of Comprehensive Income to Adjusted EBITDA (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Comprehensive income									$ 353.2	$ 140.4	$ 107.5
Foreign currency translation, net of tax									(0.6)	0.1	(0.2)
Change in pension benefits, net of tax									0.2	0.0	0.8
Net income									352.8	140.5	108.1
Income from discontinued operations, net of tax	$ (4.1)	$ 1.7	$ 0.1	$ (167.9)	$ (3.8)	$ (3.8)	$ (5.4)	$ (5.1)	(170.2)	(18.1)	(11.4)
Income from continuing operations, net of tax	$ 7.3	58.0	$ 103.2	$ 14.1	34.4	$ 12.9	$ 72.9	$ 2.2	182.6	122.4	96.7
Depreciation and amortization									63.6	97.1	108.6
Loss on extinguishment of debt					20.7				0.0	20.7	0.0
Income tax provision (benefit)									51.3	(19.9)	50.7
EBITDA									337.6	228.5	249.5
Stock-based compensation expense									21.1	27.1	18.9
Gain on Ocean Downs/Saratoga transaction		$ (54.9)							(54.9)	0.0	0.0
Impairment of tangible and other intangible assets					$ 21.7				0.0	21.7	0.0
Total adjustments to EBITDA									(8.8)	57.7	2.8
Adjusted EBITDA									328.8	286.2	252.3
Racing
Segment Reporting Information [Line Items]
Adjusted EBITDA									92.4	84.5	79.7
Online Wagering
Segment Reporting Information [Line Items]
Adjusted EBITDA									72.8	64.4	56.2
Casino
Segment Reporting Information [Line Items]
Adjusted EBITDA									169.5	146.0	125.8
Other Investments
Segment Reporting Information [Line Items]
Adjusted EBITDA									5.3	3.7	2.7
Corporate
Segment Reporting Information [Line Items]
Adjusted EBITDA									(11.2)	(12.4)	(12.1)
Big Fish Games | Discontinued Operations, Held-for-sale
Segment Reporting Information [Line Items]
Adjusted EBITDA corporate and other expenses											3.1
Big Fish Games | Discontinued Operations, Held-for-sale | Corporate
Segment Reporting Information [Line Items]
Adjusted EBITDA corporate and other expenses										3.6	3.1
Continuing Operations
Segment Reporting Information [Line Items]
Depreciation and amortization									63.6	56.0	58.4
Interest expense									40.1	49.3	43.7
Loss on extinguishment of debt									0.0	20.7	0.0
Income tax provision (benefit)									51.3	(19.9)	50.7
Stock-based compensation expense									17.7	16.0	13.3
Other, net									(0.6)	0.5	2.5
Pre-opening expense									4.8	0.5	0.0
Interest, depreciation and amortization expense related to equity investments									13.9	16.7	10.0
Other charges and recoveries, net									0.0	0.0	0.5
Gain on Ocean Downs/Saratoga transaction									(54.9)	0.0	0.0
Impairment of tangible and other intangible assets									10.3	2.3	0.2
Impairment of tangible and other intangible assets									0.0	21.7	0.0
Gain on Calder land sale									$ 0.0	$ 0.0	$ (23.7)