Acquisition (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended			13 Months Ended
	Aug. 31, 2018	Sep. 30, 2018	Sep. 30, 2017	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2017	Mar. 31, 2019	Dec. 31, 2017
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	15 months
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	$ 13.1
Repayment of Ocean Downs debt					$ 54.7	$ 0.0
Business Combination, Contingent Consideration, Asset, Current	2.1
Business Acquisition, Pro Forma Revenue		$ 240.2	$ 218.7		845.7	754.8
Business Acquisition, Pro Forma Net Income (Loss)		15.5	18.2		302.4	104.1
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	57.4
Goodwill, Acquired During Period					20.2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	95.4
Business Combination, Contingent Consideration, Liability, Current	(5.2)							$ (34.2)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt	(54.7)
Noncash or Part Noncash Acquisition, Net Nonmonetary Assets Acquired (Liabilities Assumed)	$ 115.2
Racing		37.6	38.8		243.8	228.0
Gain on Ocean Downs/Saratoga transaction		54.9	$ 0.0		$ 54.9	$ 0.0
Scenario, Forecast [Member] | Presque Isle Downs & Casino And Lady Luck Casino [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross							$ 229.5
Scenario, Forecast [Member] | Presque Isle Downs & Casino [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross				$ 178.9
Ocean Downs LLC and Racing Services LLC [Member]
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage	100.00%
Equity Method Investments	$ 80.5
Racing		$ 8.1
Saratoga Casino Holdings, LLC [Member]
Business Acquisition [Line Items]
Equity Method Investments	47.8
Game Rights [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	87.0
Trade Names [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	8.3
Other Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 0.1