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STOCK-BASED COMPENSATION PLAN - Narrative (Details) $ in Thousands |  |  |  |  |  |  |  |  | 3 Months Ended | 9 Months Ended | 12 Months Ended |
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Jun. 11, 2025 shares | Mar. 17, 2025 USD ($) segment shares | Mar. 06, 2024 USD ($) segment shares | Jan. 16, 2024 USD ($) shares | May 08, 2023 shares | Mar. 08, 2023 | Mar. 09, 2022 shares | Oct. 01, 2021 shares | Sep. 30, 2025 USD ($) shares | Jun. 30, 2025 shares | Mar. 31, 2025 | Sep. 30, 2024 USD ($) | Sep. 30, 2025 USD ($) segment shares | Sep. 30, 2024 USD ($) | Dec. 31, 2024 shares | Jun. 21, 2023 shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Compensation expense capitalized | $ |  |  |  |  |  |  |  |  | $ 0 |  |  | $ 0 | $ 0 | $ 0 |  |
Number of operating segments | segment |  | 3 | 3 |  |  |  |  |  |  |  |  |  | 3 |  |  |
Senior Management Member |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.00% |
Chief Executive Officer and Chief Financial Officer |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.00% |
President of Environmental Technologies | May 8th, 2023 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  |  |  |  |  |  |  |  |  | 50.00% |  |  |  |  |
President of Environmental Technologies | March 6th, 2024 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  |  |  |  |  |  |  |  |  | 100.00% |  |  |  |  |
President of Environmental Technologies | March 17th, 2025 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  |  |  |  |  |  |  |  |  | 100.00% |  |  |  |  |
Performance-Based Restricted Stock Granted March 17 2025 | Chief Executive Officer, Chief Financial Officer, and Division Presidents |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Granted (in shares) |  | 49,098 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Granted, fair value | $ |  | $ 400 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unvested shares outstanding (in shares) |  |  |  |  |  |  |  |  | 44,791 |  |  |  | 44,791 |  |  |
Performance-Based Restricted Stock Granted March 17 2025 | Chief Executive Officer, Chief Financial Officer, and Division Presidents | Share-Based Payment Arrangement, Tranche One |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  |  |  |  |  |  |  |  |  |  |  | 100.00% |  |  |
Performance-Based Restricted Stock Granted March 17 2025 | Chief Executive Officer, Chief Financial Officer, and Division Presidents | Share-Based Payment Arrangement, Tranche One | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  | 0.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Performance-Based Restricted Stock Granted March 17 2025 | Chief Executive Officer, Chief Financial Officer, and Division Presidents | Share-Based Payment Arrangement, Tranche One | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  | 150.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Performance-Based Restricted Stock Granted March 6 2024 | Chief Executive Officer, Chief Financial Officer, and Division Presidents |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Granted (in shares) |  |  | 33,539 |  |  |  |  |  |  |  |  |  |  |  |  |
Granted, fair value | $ |  |  | $ 400 |  |  |  |  |  |  |  |  |  |  |  |  |
Unvested shares outstanding (in shares) |  |  |  |  |  |  |  |  | 30,597 |  |  |  | 30,597 |  |  |
Performance-Based Restricted Stock Granted March 6 2024 | Chief Executive Officer, Chief Financial Officer, and Division Presidents | Share-Based Payment Arrangement, Tranche One | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  | 0.00% |  |  |  |  |  |  |  |  |  |  |  |  |
Performance-Based Restricted Stock Granted March 6 2024 | Chief Executive Officer, Chief Financial Officer, and Division Presidents | Share-Based Payment Arrangement, Tranche One | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  | 150.00% |  |  |  |  |  |  |  |  |  |  |  |  |
Performance-Based Restricted Stock Granted March 6 2024 | Chief Executive Officer, Chief Financial Officer And Other Members Of Senior Management | Share-Based Payment Arrangement, Tranche One |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  |  |  |  |  |  |  | 50.00% | 100.00% |  |  |  |  |  |
Performance Shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Granted (in shares) |  |  |  |  |  |  |  |  |  |  |  |  | 49,098 |  |  |
Unvested shares outstanding (in shares) |  |  |  |  |  |  |  |  | 100,224 |  |  |  | 100,224 |  | 88,949 |
Forfeited (in shares) |  |  |  |  |  |  |  |  |  |  |  |  | 37,823 |  |  |
Performance Shares | Senior Management Member |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Granted (in shares) |  |  |  |  |  |  |  | 5,000 |  |  |  |  |  |  |  |
Performance Shares | Chief Executive Officer and Chief Financial Officer |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Granted (in shares) |  |  |  |  |  |  | 20,493 |  |  |  |  |  |  |  |  |
Performance Shares | Chief Executive Officer, Chief Financial Officer And Other Members Of Senior Management |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unvested shares outstanding (in shares) |  |  |  |  |  |  |  |  | 16,605 | 16,605 |  |  | 16,605 |  |  |
Performance Shares | Chief Executive Officer, Chief Financial Officer And Other Members Of Senior Management | Share-Based Payment Arrangement, Tranche One | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  |  |  |  | 0.00% |  |  |  |  |  |  |  |  |  |
Options vesting period |  |  |  |  |  | 3 years |  |  |  |  |  |  |  |  |  |
Performance Shares | Chief Executive Officer, Chief Financial Officer And Other Members Of Senior Management | Share-Based Payment Arrangement, Tranche One | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  |  |  |  | 150.00% |  |  |  |  |  |  |  |  |  |
Performance Shares | Chief Executive Officer, Chief Financial Officer And Other Members Of Senior Management | Share-Based Payment Arrangement, Tranche Two |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  |  |  |  |  |  |  |  | 0.00% | 50.00% |  |  |  |  |
Performance Shares | President of Environmental Technologies |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Granted (in shares) |  | 4,307 | 2,942 |  | 5,081 |  |  |  |  |  |  |  |  |  |  |
Forfeited (in shares) | 12,330 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Performance-Based Restricted Stock Granted January 16 2024 | President of Process Technologies |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Granted (in shares) |  |  |  | 8,231 |  |  |  |  |  |  |  |  |  |  |  |
Granted, fair value | $ |  |  |  | $ 100 |  |  |  |  |  |  |  |  |  |  |  |
Performance-Based Restricted Stock Granted January 16 2024 | President of Process Technologies | Share-Based Payment Arrangement, Tranche One |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  |  |  |  |  |  |  | 0.00% | 100.00% |  |  |  |  |  |
Performance-Based Restricted Stock Granted January 16 2024 | President of Process Technologies | Share-Based Payment Arrangement, Tranche One | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  |  | 0.00% |  |  |  |  |  |  |  |  |  |  |  |
Performance-Based Restricted Stock Granted January 16 2024 | President of Process Technologies | Share-Based Payment Arrangement, Tranche One | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Vesting rights percentage |  |  |  | 150.00% |  |  |  |  |  |  |  |  |  |  |  |
The 2023 Stock Incentive Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Shares available for issuance (in shares) (up to) |  |  |  |  |  |  |  |  | 350,000 |  |  |  | 350,000 |  |  |
Shares available for grant and issuance (in shares) |  |  |  |  |  |  |  |  | 436,980 |  |  |  | 436,980 |  |  | 1,117,942
Shares reserved for future issuance (in shares) |  |  |  |  |  |  |  |  | 50,113 |  |  |  | 50,113 |  |  |
Unrecognized compensation expense | $ |  |  |  |  |  |  |  |  | $ 3,900 |  |  |  | $ 3,900 |  |  |
Unrecognized compensation expense, period for recognition |  |  |  |  |  |  |  |  |  |  |  |  | 2 years 7 months 6 days |  |  |

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