Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022	Nov. 18, 2021	Oct. 08, 2021
Class of Stock [Line Items]
Equity Securities Registered, Value						$ 750.0
At-the-market Equity Offering Program, Common Stock Available for Issuance	$ 298.2		$ 298.2		$ 300.0
At-the-market Equity Offering Program, Common Stock Issued			0
Common Stock, Shares Authorized	$ 748.2		$ 748.2
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	512,545
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 14.76
Stock-based compensation expense	$ 1.9	$ 1.6	2.5	$ 2.0
Retirement Eligible
Class of Stock [Line Items]
Stock-based compensation expense	$ 1.3	$ 1.2	$ 1.3	$ 1.2