DERIVATIVE INSTRUMENTS - CREDIT RISK EXPOSURE (Details) $ in Thousands	3 Months Ended
Dec. 31, 2019 USD ($)
Credit Risk Exposure [Line Items]
Gross Credit Exposure	$ 288,834
Investment grade
Credit Risk Exposure [Line Items]
Gross Credit Exposure	197,369
Noninvestment grade
Credit Risk Exposure [Line Items]
Gross Credit Exposure	17,822
Internally rated investment grade
Credit Risk Exposure [Line Items]
Gross Credit Exposure	38,312
Internally rated noninvestment grade
Credit Risk Exposure [Line Items]
Gross Credit Exposure	$ 35,331

Maximum amount of loss due to credit risk that, based on the gross fair value of the financial instrument, the entity would incur if parties to the financial instruments that make up the concentration failed completely to perform according to the terms of the contracts and the collateral or other security, if any, for the amount due proved to be of no value to the entity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13537-108611

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration