Quarterly Results of Operations (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Net revenues	$ 278.2	$ 337.8	$ 185.1	$ 252.9	$ 280.6	$ 306.3	$ 477.4	$ 265.4	$ 1,054.0	$ 1,329.7	$ 1,009.0
Operating (loss) income	22.7	49.5	(0.4)	(11.6)	3.5	27.8	156.4	28.0	60.2	215.7	188.8
(Loss) income from continuing operations, net of tax	16.4	43.1	(23.6)	(22.6)	4.2	15.2	108.3	11.9	13.3	139.6	182.6
(Loss) income from discontinued operations, net of tax	$ 0.7	$ 0.0	$ (95.2)	$ (0.9)	$ (0.5)	$ (0.4)	$ (1.2)	$ (0.3)	$ (95.4)	$ (2.4)	$ 170.2
Net income (loss) per common share data - basic:
Continuing operations (in dollars per share)	$ 0.41	$ 1.09	$ (0.59)	$ (0.57)	$ 0.11	$ 0.38	$ 2.70	$ 0.30	$ 0.34	$ 3.49	$ 4.42
Discontinued operations (in dollars per share)	0.02	0	(2.41)	(0.02)	(0.01)	(0.01)	(0.03)	(0.01)	(2.41)	(0.06)	4.12
Net income per common share - basic (in dollars per share)	0.43	1.09	(3.00)	(0.59)	0.10	0.37	2.67	0.29	(2.07)	3.43	8.54
Net income (loss) per common share data - diluted:
Continuing operations (in dollars per share)	0.41	1.08	(0.59)	(0.57)	0.11	0.37	2.66	0.30	0.33	3.44	4.39
Discontinued operations (in dollars per share)	0.02	0	(2.41)	(0.02)	(0.01)	(0.01)	(0.03)	(0.01)	(2.41)	(0.06)	4.09
Net income per common share - diluted (in dollars per share)	$ 0.43	$ 1.08	$ (3.00)	$ (0.59)	$ 0.10	$ 0.36	$ 2.63	$ 0.29	$ (2.08)	$ 3.38	$ 8.48
Finite-Lived Intangible Assets [Line Items]
Amortization of definite-lived intangible assets									$ 4.9	$ 15.0	$ 6.0
Turfway Park
Finite-Lived Intangible Assets [Line Items]
Amortization of definite-lived intangible assets					$ 10.0