Long-Term Debt (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Sep. 30, 2025	Mar. 10, 2022
Debt Instrument
Long-term and short-term debt, combined amount	$ 1,190.0		$ 1,090.0
Unamortized Debt Issuance Expense	(5.4)		(5.7)
Long-term debt	1,184.6		1,084.3
7.00% Senior Notes Maturing in March 2030
Debt Instrument
Long-Term Debt, Gross	840.0		840.0
Revolving Credit Facility
Debt Instrument
Long-Term Debt, Gross	350.0		250.0
Maximum borrowing capacity on line of credit	500.0			$ 250.0
Proceeds from borrowing under line of credit	180.0	$ 35.0
Repayments of lines of credit	80.0	35.0
Line of Credit Facility [Line Items]
Proceeds from borrowing under line of credit	180.0	$ 35.0
Remaining borrowing capacity on line of credit	147.6		247.6
Letters of credit outstanding, amount	2.4		$ 2.4
Letter of Credit
Debt Instrument
Maximum borrowing capacity on line of credit	$ 20.0