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EMPLOYEE BENEFIT PLANS - Schedule of net periodic costs (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023
Net periodic (benefits) costs: |  |  |
Pension termination settlement | $ (4,621) |  |
Amortization of: |  |  |
Total net periodic (benefits) costs | (5,411) | $ 137 | $ 866
Pension Plan |  |  |
Net periodic (benefits) costs: |  |  |
Interest cost | 5,506 | 7,050 | 6,814
Expected return on plan assets | (9,387) | (10,172) | (10,213)
Pension termination settlement | (4,621) | 0 | 0
Amortization of: |  |  |
Actuarial loss | 2,087 | 2,250 | 3,314
Total net periodic (benefits) costs | (6,415) | (872) | (85)
Supplemental Employee Retirement Plan |  |  |
Net periodic (benefits) costs: |  |  |
Interest cost | 387 | 504 | 488
Expected return on plan assets | 0 | 0 | 0
Pension termination settlement | 0 | 0 | 0
Amortization of: |  |  |
Actuarial loss | 617 | 505 | 463
Total net periodic (benefits) costs | $ 1,004 | $ 1,009 | $ 951

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- Definition Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480535/715-20-45-3A Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-18 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-6 + Details
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