Business - Additional Information (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2021 USD ($) Segment $ / shares shares	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2019 USD ($)
Business [Line Items]
Number of reportable segments | Segment	2
Repayments of debt | $	$ 10.4	$ 10.4	$ 13.0
Common stock, authorized	500,000,000	500,000,000
Preferred Stock, Shares Authorized	50,000,000	50,000,000
Preferred stock, par value | $ / shares	$ 0.01	$ 0.01