REVENUE FROM CONTRACTS WITH CUSTOMERS - Narrative (Details) - USD ($) $ in Millions |
3 Months Ended | ||
|---|---|---|---|
Dec. 31, 2024 |
Dec. 31, 2023 |
Sep. 30, 2024 |
|
| Revenue from Contract with Customer [Abstract] | |||
| Revenue from performance contracts | $ 305.8 | $ 298.2 | |
| Performance bonuses recognized | 16.9 | 15.2 | |
| Early termination revenue | 1.4 | $ 5.4 | |
| Capitalized fulfillment costs | $ 29.9 | $ 19.2 | |