VARIABLE INTEREST ENTITIES - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Variable Interest Entities
Variable Interest Entity [Line Items]
Investment banking and advisory fee revenue	$ 3.1	$ 2.7

Amount of fees and commissions from banking, advisory, brokerage, and securities underwriting activities. Activities include, but are not limited to, underwriting securities, private placements of securities, investment advisory and management services, merger and acquisition services, sale and servicing of mutual funds, and other related consulting fees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.13(b))
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Name:	us-gaap_InvestmentBankingAdvisoryBrokerageAndUnderwritingFeesAndCommissions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration