Earnings (Loss) per Share - Antidilutive Securities and Reconciliation of Weighted-Average Common Shares Outstanding (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Assumed conversion of convertible debt (in shares)	14,100,000	0	0	0
Net Income (Loss) Attributable to Parent, Diluted [Abstract]
Net income (loss) attributable to Penn National	$ 141.9	$ 43.9	$ (680.6)	$ 136.4
Net income applicable to preferred stock	0.8	0.0	0.0	0.0
Net income (loss) applicable to common stock	$ 141.1	$ 43.9	$ (680.6)	$ 136.4
Weighted-average number of shares outstanding
Weighted - average common shares outstanding - Basic (in shares)	138,200,000	115,200,000	126,900,000	115,800,000
Convertible debt (in shares)	14,100,000	0	0	0
Weighted-average common shares outstanding - Diluted (in shares)	155,500,000	116,700,000	126,900,000	117,700,000
Stock options
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Assumed conversion of dilutive stock options and dilutive RSAs (in shares)	2,800,000	1,400,000	0	1,700,000
Weighted-average number of shares outstanding
Dilutive stock options and dilutive RSAs (in shares)	2,800,000	1,400,000	0	1,700,000
Restricted stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Assumed conversion of dilutive stock options and dilutive RSAs (in shares)	400,000	100,000	0	200,000
Weighted-average number of shares outstanding
Dilutive stock options and dilutive RSAs (in shares)	400,000	100,000	0	200,000
Stock options
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Assumed conversion of dilutive stock options and dilutive RSAs (in shares)			2,500,000
Weighted-average number of shares outstanding
Dilutive stock options and dilutive RSAs (in shares)			2,500,000
Anti-dilutive securities (in shares)	0	2,500,000	900,000	2,100,000
Restricted stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Assumed conversion of dilutive stock options and dilutive RSAs (in shares)			400,000
Weighted-average number of shares outstanding
Dilutive stock options and dilutive RSAs (in shares)			400,000
Convertible Preferred Shares
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Assumed conversion of convertible preferred shares (in shares)			700,000
Weighted-average number of shares outstanding
Anti-dilutive securities (in shares)	800,000
Convertible Debt
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Assumed conversion of convertible debt (in shares)			7,400,000
Weighted-average number of shares outstanding
Convertible debt (in shares)			7,400,000