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Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Class of Stock [Line Items]
Equity Securities Registered, Value	$ 750.0		$ 750.0
At-the-market Equity Offering Program, Common Stock Available for Issuance	300.0		300.0
Common Stock, Shares Authorized	750.0		750.0
Stock-based compensation expense	1.5	$ 1.4	$ 5.8	$ 4.1
October Two Thousand Twenty Four Grant \| Performance Shares
Class of Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			99,097
Stock-based compensation expense	0.3		$ 0.9
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 35.20
October Two Thousand Twenty Four Grant \| Performance Shares \| Minimum
Class of Stock [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage			0.00%
October Two Thousand Twenty Four Grant \| Performance Shares \| Maximum
Class of Stock [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage			200.00%
First Quarter Two Thousand Twenty Five time-based RSU Grants \| Time-Based RSU
Class of Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			306,300
Stock-based compensation expense	$ 1.2		$ 4.9
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 29.00
First Quarter Two Thousand Twenty Five time-based RSU Grants \| Time-Based RSU \| Retirement Eligible
Class of Stock [Line Items]
Stock-based compensation expense			$ 1.1	$ 0.7