LONG-TERM DEBT - Schedule of Long-term Debt (Details) - USD ($) $ in Millions	Mar. 31, 2026	Sep. 30, 2025
Debt Instrument
Total principal amount of debt	$ 1,190.0	$ 1,090.0
Less: Debt issuance costs, net	5.0	5.7
Long-term debt	1,185.0	1,084.3
Line of Credit | Amended Credit Agreement, JP Morgan Chase Administrator | Revolving Credit Facility
Debt Instrument
Total principal amount of debt	350.0	250.0
Senior Notes | 7.00% Senior Notes Maturing in March 2030
Debt Instrument
Total principal amount of debt	$ 840.0	$ 840.0