INVESTMENTS - Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Sep. 30, 2023
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Contractual maturities of available-for-sale securities due within one year	$ 38,700	$ 74,700
Contractual maturities of available-for-sale securities due beyond one year to five years	10,200	1,300
Contingent Consideration
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Acquisition-related contingent consideration	$ 0	$ 7,976