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STOCKHOLDERS' EQUITY AND EQUITY COMPENSATION - Narrative (Details) |  |  |  | 1 Months Ended | 12 Months Ended |  |  |  |
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Aug. 21, 2020 USD ($) $ / shares shares | Aug. 21, 2020 USD ($) $ / shares shares | Aug. 18, 2020 USD ($) $ / shares shares | Jan. 29, 2016 shares | Aug. 31, 2020 USD ($) $ / shares shares | Sep. 30, 2021 USD ($) unit $ / shares shares | Sep. 30, 2020 USD ($) $ / shares | Sep. 30, 2019 USD ($) $ / shares | Jan. 30, 2020 shares | Aug. 01, 2018 USD ($) | Jan. 31, 2018 shares | Aug. 03, 2016 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Common stock, dividends, per share, cash paid (in dollars per share) | $ / shares |  |  |  |  |  | $ 0.32 | $ 0.30 | $ 0.29 |  |  |  |
Accrued dividends | $ |  |  |  |  |  | $ 2,920,000 |  |  |  |  |  |
Sale of stock, number of shares issued (in shares) | 8,700,000 | 700,000 | 8,000,000 |  | 8,700,000 |  |  |  |  |  |  |
Sale of stock, stock price (in dollars per share) | $ / shares | $ 21.50 | $ 21.50 | $ 21.50 |  | $ 21.50 |  |  |  |  |  |  |
Net process from sale of stock | $ | $ 178,165,000 | $ 14,335,000 | $ 163,830,000 |  | $ 178,165,000 |  |  |  |  |  |  |
Share-based payment award, number of shares authorized (in shares) |  |  |  |  |  | 4,354,429 |  |  |  |  |  |
Stock repurchase program, authorized amount | $ |  |  |  |  |  |  |  |  |  | $ 50,000,000 |  | $ 50,000,000
Stock repurchased during period (in shares) |  |  |  |  |  | 0 |  |  |  |  |  |
Stock repurchase program, remaining authorized repurchase amount | $ |  |  |  |  |  | $ 57,955,000 |  |  |  |  |  |
Shares paid for tax withholding for share based compensation (in shares) |  |  |  |  |  | 152,435 |  |  |  |  |  |
Shares paid for tax withholding for share based compensation, value | $ |  |  |  |  |  | $ 3,222,000 |  |  |  |  |  |
Shares paid for tax withholding for share based compensation, value per share (in dollars per share) | $ / shares |  |  |  |  |  | $ 21.14 |  |  |  |  |  |
Restricted Stock and Restricted Stock Units |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Instruments grants in period (in shares) |  |  |  |  |  | 1,242,906 |  |  |  |  |  |
Restricted Stock and Restricted Stock Units | Minimum |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, award vesting period |  |  |  |  |  | 3 years |  |  |  |  |  |
Restricted Stock and Restricted Stock Units | Maximum |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, award vesting period |  |  |  |  |  | 4 years |  |  |  |  |  |
Restricted Stock and Restricted Stock Units, Subject To Performance Conditions |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, award vesting period |  |  |  |  |  | 3 years |  |  |  |  |  |
Instruments grants in period (in shares) |  |  |  |  |  | 226,811 |  |  |  |  |  |
Instruments vested in period, fair value | $ |  |  |  |  |  | $ 5,500,000 |  |  |  |  |  |
Weighted average grant date fair value (in dollars per share) | $ / shares |  |  |  |  |  | $ 24.25 |  |  |  |  |  |
Restricted Stock |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, options, vested in period, fair value | $ |  |  |  |  |  | $ 10,627,000 | $ 17,889,000 | $ 4,748,000 |  |  |  |
Employee service share-based compensation, nonvested awards, compensation not yet recognized, share-based awards other than options | $ |  |  |  |  |  | $ 29,686,000 |  |  |  |  |  |
Employee service share-based compensation, nonvested awards, compensation cost not yet recognized, period for recognition |  |  |  |  |  | 2 years 6 months |  |  |  |  |  |
Instruments grants in period (in shares) |  |  |  |  |  | 1,287,330 |  |  |  |  |  |
Weighted average grant date fair value (in dollars per share) | $ / shares |  |  |  |  |  | $ 19.61 |  |  |  |  |  |
Instruments vested in period (in shares) |  |  |  |  |  | 498,333 |  |  |  |  |  |
Shares paid for tax withholding for share based compensation (in shares) |  |  |  |  |  | 6,507 |  |  |  |  |  |
Shares paid for tax withholding for share based compensation, value | $ |  |  |  |  |  | $ 135,000 |  |  |  |  |  |
Shares paid for tax withholding for share based compensation, value per share (in dollars per share) | $ / shares |  |  |  |  |  | $ 20.75 |  |  |  |  |  |
Director | Restricted Stock and Restricted Stock Units |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, award vesting period |  |  |  |  |  | 3 years |  |  |  |  |  |
Instruments grants in period (in shares) |  |  |  |  |  | 44,424 |  |  |  |  |  |
Instruments vested in period, fair value | $ |  |  |  |  |  | $ 1,080,000 |  |  |  |  |  |
Weighted average grant date fair value (in dollars per share) | $ / shares |  |  |  |  |  | $ 24.31 |  |  |  |  |  |
Executive Officer | Restricted Stock |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Instruments grants in period (in shares) |  |  |  |  |  | 488,095 |  |  |  |  |  |
Instruments number of persons granted shares (in shares) | unit |  |  |  |  |  | 6 |  |  |  |  |  |
Executive Officer | Restricted Stock | Minimum |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, award vesting period |  |  |  |  |  | 34 months |  |  |  |  |  |
Executive Officer | Restricted Stock | Maximum |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, award vesting period |  |  |  |  |  | 60 months |  |  |  |  |  |
Instruments vested in period, fair value | $ |  |  |  |  |  | $ 10,836,000 |  |  |  |  |  |
Weighted average grant date fair value (in dollars per share) | $ / shares |  |  |  |  |  | $ 22.20 |  |  |  |  |  |
Senior Executives | Restricted Stock, Subject to Performance Conditions |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, award vesting period |  |  |  |  |  | 4 years |  |  |  |  |  |
Instruments grants in period (in shares) |  |  |  |  |  | 528,000 |  |  |  |  |  |
Weighted average grant date fair value (in dollars per share) | $ / shares |  |  |  |  |  | $ 14.82 |  |  |  |  |  |
Instruments number of persons granted shares (in shares) | unit |  |  |  |  |  | 2 |  |  |  |  |  |
Post-vesting holding period |  |  |  |  |  | 2 years |  |  |  |  |  |
Equity instruments other than options, granted in period, fair value | $ |  |  |  |  |  | $ 7,824,000 |  |  |  |  |  |
Senior Executives | Restricted Stock, Subject to Performance Conditions | Minimum |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Instruments vested in period (in shares) |  |  |  |  |  | 384,000 |  |  |  |  |  |
Senior Executives | Restricted Stock, Subject to Performance Conditions | Maximum |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Instruments vested in period (in shares) |  |  |  |  |  | 528,000 |  |  |  |  |  |
Incentive Plan |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, number of shares authorized (in shares) |  |  |  | 5,050,000 |  |  |  |  | 1,700,000 |  | 1,000,000 |
Share-based payment award, expiration period |  |  |  | 10 years |  |  |  |  |  |  |  |
Maximum percentage of exercise price at grant date fair value |  |  |  | 100.00% |  |  |  |  |  |  |  |
Share-based payment award, number of shares available for grant (in shares) |  |  |  |  |  | 488,376 |  |  |  |  |  |
Incentive Plan | Incentive Stock Options |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Stock issued during period, shares, new issues (in shares) |  |  |  | 600,000 |  |  |  |  |  |  |  |

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- Definition Amount remaining of a stock repurchase plan authorized. + References No definition available. + Details
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- Definition Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Details
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- Details
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- Details
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- Details
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- Details
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- Details
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