Earnings (Loss) 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, 2022	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net income (loss) available to common stockholders		$ 14.0	$ 46.3	$ (41.6)
Weighted average number of common shares outstanding – basic		97,898,000	105,183,000	103,670,000
Basic income (loss) per share		$ 0.14	$ 0.44	$ (0.40)
Weighted average number of common shares outstanding – diluted		98,161,000	105,690,000	103,670,000
Diluted income (loss) per share		$ 0.14	$ 0.44	$ (0.40)
Weighted average number of anti-dilutive options and restricted stock	[1]	5,010,000	7,452,000	8,210,000

[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.