EMPLOYEE BENEFIT PLANS - COMPONENTS OF NET PERIODIC COST (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2026 |
Mar. 31, 2025 |
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| Pension | ||||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||
| Service cost | $ 1,244 | $ 1,380 | $ 2,489 | $ 2,761 |
| Interest cost | 3,963 | 3,859 | 7,927 | 7,717 |
| Expected return on plan assets | (6,137) | (5,925) | (12,274) | (11,850) |
| Recognized actuarial loss | 39 | 300 | 77 | 601 |
| Prior service credit amortization | 0 | 0 | 0 | 0 |
| Net periodic benefit (credit) cost | (891) | (386) | (1,781) | (771) |
| OPEB | ||||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||
| Service cost | 272 | 273 | 544 | 546 |
| Interest cost | 2,698 | 2,097 | 5,396 | 4,194 |
| Expected return on plan assets | (2,260) | (2,347) | (4,519) | (4,693) |
| Recognized actuarial loss | 2,796 | 1,793 | 5,592 | 3,586 |
| Prior service credit amortization | (3,270) | (3,270) | (6,540) | (6,540) |
| Net periodic benefit (credit) cost | $ 236 | $ (1,454) | $ 473 | $ (2,907) |
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- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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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. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of cost recognized for passage of time related to defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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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. No definition available.
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