(Loss) Earnings Per Share of Common Stock - Reconciliation of Numerator and Denominator for Basic and Diluted Earnings (loss) Per Share Calculation (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Share [Abstract]
Net income (loss)		$ (7.7)	$ 14.0	$ 46.3
Dividends on Series A convertible preferred stock		(3.2)
Earnings allocated to Convertible Preferred Stock		0.0	0.0	0.0
Net (loss) income attributable to common stockholders		$ (10.9)	$ 14.0	$ 46.3
Weighted average number of common shares outstanding – basic		93,412,000	97,898,000	105,183,000
Basic (loss) earnings per share		$ (0.12)	$ 0.14	$ 0.44
Net (loss) income available to common shareholders - diluted		$ (10.9)	$ 14.0	$ 46.3
Stock compensation awards		0	263,000,000,000	507,000,000,000
Weighted average number of common shares outstanding – diluted		93,412,000	98,161,000	105,690,000
Diluted (loss) earnings per share		$ (0.12)	$ 0.14	$ 0.44
Weighted average number of anti-dilutive options, restricted stock and Series A convertible preferred shares on an as-converted basis (a)	[1]	9,656,000	5,010,000	7,452,000

[1] Weighted average number of anti-dilutive options is based upon the average closing price of the Company’s common stock on the NYSE for the period.