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STOCK-BASED COMPENSATION - NARRATIVE (Details) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares available for future issuance (in shares) | 3,189,550 |  |  |
Performance Shares, Market Condition Award |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) | 33,123 | 36,392 | 31,836 |
Performance Shares, Subject to Performance Conditions |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) | 48,941 | 63,870 | 59,341 |
Deferred compensation related to unvested performance shares, period | 1 year 8 months 12 days |  |  |
Performance share awards |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) | 155,731 | 130,509 | 145,176 | 156,587
Deferred compensation related to unvested restricted and performance shares | $ 2,400 |  |  |
Restricted Stock |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) | 73,486 | 58,156 | 44,168 | 51,154
Deferred compensation related to unvested restricted and performance shares | $ 1,000 |  |  |
Deferred compensation related to unvested performance shares, period | 1 year 9 months 18 days |  |  |
Vesting September 30, 2022 | Performance Shares, Subject to Performance Conditions |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) | 30,473 |  |  |
Vesting Annually Over Three Year Period Beginning September 2020 | Performance Shares, Subject to Performance Conditions |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) | 18,468 |  |  |
Award vesting period | 3 years |  |  |
Vesting September 30, 2021 | Performance Shares, Subject to Performance Conditions |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) |  | 33,844 |  |
Vesting Annually Over Three Year Period Beginning September 30, 2019 | Performance Shares, Subject to Performance Conditions |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) |  | 30,026 |  |
Award vesting period |  | 3 years |  |
Vesting September 30, 2020 | Performance Shares, Subject to Performance Conditions |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) |  |  | 29,608 |
Vesting Annually Over Three Year Period Beginning September 30, 2018 | Performance Shares, Subject to Performance Conditions |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) |  |  | 29,733 |
Award vesting period |  |  | 3 years |
Vesting Annually Over Three Year Period Beginning October 2020 | Restricted Stock |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) | 42,478 |  |  |
Award vesting period | 3 years |  |  |
Vesting Annually Over Three Year Period Beginning October 2019 | Restricted Stock |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) |  | 29,222 |  |
Award vesting period |  | 3 years |  |
Vesting Annually Over Three Year Period Beginning April 2020 | Restricted Stock |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) |  | 6,062 |  |
Award vesting period |  | 3 years |  |
Vesting Annually Over Three Year Period Beginning October 2018 | Restricted Stock |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares granted but not issued (in shares) |  |  | 27,949 |
Award vesting period |  |  | 3 years |

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- Definition Amount of cost not yet recognized for nonvested award under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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