EMPLOYEE BENEFIT PLANS - Weighted-average assumptions used in determining the net periodic benefit costs (Details)	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.30%	2.92%	4.10%
Expected return on assets	6.75%	7.00%	7.00%
Weighted average discount rate	2.58%	2.30%
Supplemental Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	1.69%	2.64%	3.99%
Expected return on assets	0.00%	0.00%	0.00%
Weighted average discount rate	1.94%	1.69%

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

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- Definition

Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan.

+ References

+ Details

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- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(3)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e2919-114920

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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