Earnings (Loss) per Share - Antidilutive Securities and Reconciliation of Weighted-Average Common Shares Outstanding (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net Income (Loss) Attributable to Parent, Diluted [Abstract]
Net income (loss) attributable to Penn National	$ 86.1	$ 141.9	$ 375.8	$ (680.6)
Net income applicable to preferred stock	0.4	0.8	1.9	0.0
Net income (loss) applicable to common stock	$ 85.7	$ 141.1	$ 373.9	$ (680.6)
Weighted-average number of shares outstanding
Weighted - average common shares outstanding (in shares)	156.1	138.2	155.9	126.9
Convertible debt (in shares)	14.1	14.1	14.1	0.0
Weighted-average common shares outstanding - Diluted (in shares)	172.7	155.5	172.7	126.9
Anti-dilutive securities (in shares)	0.2	0.0	0.2	0.9
Stock options
Weighted-average number of shares outstanding
Dilutive stock options and dilutive RSAs (in shares)	2.1	2.8	2.3	0.0
Restricted stock
Weighted-average number of shares outstanding
Dilutive stock options and dilutive RSAs (in shares)	0.4	0.4	0.4	0.0
Restricted stock
Weighted-average number of shares outstanding
Dilutive stock options and dilutive RSAs (in shares)				0.4
Convertible Preferred Shares
Weighted-average number of shares outstanding
Anti-dilutive securities (in shares)	0.8		0.8