LONG-TERM DEBT - Schedule of Long-term Debt (Details) - USD ($) $ in Millions	Jun. 30, 2026	Sep. 30, 2025	Aug. 22, 2025
Debt Instrument
Total principal amount of debt	$ 1,140.0	$ 1,090.0
Less: Debt issuance costs, net	4.7	5.7
Long-term debt	1,135.3	1,084.3
Line of Credit \| Amended Credit Agreement, JP Morgan Chase Administrator \| Revolving Credit Facility
Debt Instrument
Total principal amount of debt	$ 300.0	$ 250.0
Interest rate	5.62%	6.14%
Senior Notes \| 7.00% Senior Notes Maturing in March 2030
Debt Instrument
Total principal amount of debt	$ 840.0	$ 840.0
Interest rate			7.00%

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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