REVENUE FROM CONTRACTS WITH CUSTOMERS - Narrative (Details) $ in Millions	3 Months Ended
Dec. 31, 2019 USD ($) month	Dec. 31, 2018 USD ($)	Sep. 30, 2019 USD ($)
Revenue from Contract with Customer [Abstract]
Early termination revenue	$ 0.1	$ 7.1
Capitalized cost	$ 14.3		$ 13.9
Number of months of unsatisfied performance obligations represent in our backlog relating to contract that currently contain month-to-month terms \| month	1

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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=68051541&loc=SL49131252-203054

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