Earnings (Loss) per Share - Antidilutive Securities and Reconciliation of Weighted-Average Common Shares Outstanding (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net Income (Loss) Attributable to Parent, Diluted [Abstract]
Net income (loss) attributable to Penn National	$ 91.0	$ (608.6)
Net income applicable to preferred stock	0.5	0.0
Net income (loss) applicable to common stock	$ 90.5	$ (608.6)
Weighted-average number of shares outstanding
Weighted - average common shares outstanding - Basic (in shares)	155.7	115.7
Convertible debt (in shares)	14.1	0.0
Weighted-average common shares outstanding - Diluted (in shares)	172.8	115.7
Stock options
Weighted-average number of shares outstanding
Dilutive stock options and dilutive RSAs (in shares)	2.6	0.0
Restricted stock
Weighted-average number of shares outstanding
Dilutive stock options and dilutive RSAs (in shares)	0.4	0.0
Stock options
Weighted-average number of shares outstanding
Anti-dilutive securities (in shares)	0.2	1.2
Restricted stock
Weighted-average number of shares outstanding
Dilutive stock options and dilutive RSAs (in shares)	0.3
Convertible Preferred Shares
Weighted-average number of shares outstanding
Anti-dilutive securities (in shares)	0.8