Long-Term Debt - Repayments (Details) $ in Millions	3 Months Ended	9 Months Ended
Long-Term Debt - Repayments (Details) $ in Millions	Jun. 30, 2026 USD ($)	Jun. 30, 2026 USD ($)	Jun. 30, 2025 USD ($)
Debt Disclosure [Abstract]
Debt Covenant, Leverage Ratio	4.25	4.25
Debt Covenant, Percentage of Revolving Credit Commitments	30.00%	30.00%
Extinguishment of Debt [Line Items]
Gross Repayments of Long-term debt	$ 45.0	$ 2,041.2	$ 466.1
Location, Statement of Income, Balance: post:LossGainOnExtinguishmentOfDebtNet
Extinguishment of Debt [Line Items]
Payment (Proceeds) for debt discounts and premiums	0.0	22.6	4.4
Write off of Debt Issuance Costs and Deferred Financing Fees	0.0	4.4	1.4
Write-off of Unamortized Debt Discount/(Premium)	0.0	(9.5)	0.0
Municipal Bonds
Extinguishment of Debt [Line Items]
Gross Repayments of Long-term debt		1.2	1.2
Municipal Bonds \| Location, Statement of Income, Balance: post:LossGainOnExtinguishmentOfDebtNet
Extinguishment of Debt [Line Items]
Payment (Proceeds) for debt discounts and premiums		0.0	0.0
Write off of Debt Issuance Costs and Deferred Financing Fees		0.0	0.0
Write-off of Unamortized Debt Discount/(Premium)		0.0	0.0
Revolving Credit Facility
Extinguishment of Debt [Line Items]
Gross Repayments of Long-term debt	45.0	805.0
Revolving Credit Facility \| Location, Statement of Income, Balance: post:LossGainOnExtinguishmentOfDebtNet
Extinguishment of Debt [Line Items]
Payment (Proceeds) for debt discounts and premiums	0.0	0.0
Write off of Debt Issuance Costs and Deferred Financing Fees	0.0	0.0
Write-off of Unamortized Debt Discount/(Premium)	$ 0.0	0.0
5.625% senior notes maturing January 2028 \| Senior Notes
Extinguishment of Debt [Line Items]
Gross Repayments of Long-term debt			464.9
5.625% senior notes maturing January 2028 \| Senior Notes \| Location, Statement of Income, Balance: post:LossGainOnExtinguishmentOfDebtNet
Extinguishment of Debt [Line Items]
Payment (Proceeds) for debt discounts and premiums			4.4
Write off of Debt Issuance Costs and Deferred Financing Fees			1.4
Write-off of Unamortized Debt Discount/(Premium)			$ 0.0
5.50% Senior Notes Maturing in December 2029 \| Senior Notes
Extinguishment of Debt [Line Items]
Gross Repayments of Long-term debt		1,235.0
5.50% Senior Notes Maturing in December 2029 \| Senior Notes \| Location, Statement of Income, Balance: post:LossGainOnExtinguishmentOfDebtNet
Extinguishment of Debt [Line Items]
Payment (Proceeds) for debt discounts and premiums		22.6
Write off of Debt Issuance Costs and Deferred Financing Fees		4.4
Write-off of Unamortized Debt Discount/(Premium)		$ (9.5)