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

Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 340
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479483/340-40-50-3

Name:	us-gaap_CapitalizedContractCostNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant