Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			9 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Nov. 30, 2021
Class of Stock [Line Items]
Equity Securities Registered, Value	$ 750.0			$ 750.0
At-the-market Equity Offering Program, Common Stock Available for Issuance	278.1			$ 278.1		$ 300.0
At-the-market Equity Offering Program, Common Stock Issued				546,174
Stock Issued During Period, Value, New Issues		$ 19.7		$ 19.7
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs				0.4
Common Stock, Shares Authorized	728.1			$ 728.1
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period				178,034
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value				$ 37.94
Stock-based compensation expense	$ 1.4		$ 0.9	$ 4.1	$ 3.4