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, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Net income (loss) available to common stockholders		$ 10.8	$ 25.2	$ (1.3)	$ 19.5
Weighted average number of common shares outstanding – basic		93,207,000	105,202,000	102,705,000	105,177,000
Basic income (loss) per share		$ 0.12	$ 0.24	$ (0.01)	$ 0.19
Weighted average number of common shares outstanding – diluted		93,436,000	105,947,000	102,705,000	105,662,000
Diluted income (loss) per share		$ 0.12	$ 0.24	$ (0.01)	$ 0.18
Weighted average number of anti-dilutive options and restricted stock	[1]	4,180,000	6,897,000	4,968,000	7,468,000

[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