EMPLOYEE BENEFIT PLANS - Change in fair value (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Change in plan assets
Fair value of plan assets at beginning of year	$ 92,816	$ 90,748
Fair value of plan assets at end of year	94,897	92,816
(Level 3)
Change in plan assets
Fair value of plan assets at beginning of year	97	177
Unrealized gains (losses) relating to property still held at the reporting date	19	(80)
Fair value of plan assets at end of year	$ 116	$ 97

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets still held.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(5)(iv)(02)(A)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

+ Details

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Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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- Definition

Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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