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EMPLOYEE BENEFIT PLANS, FAIR VALUE (Details) - USD ($) $ in Thousands | Sep. 30, 2016 | Sep. 30, 2015 | Sep. 30, 2014
--- | --- | --- | ---
Pension |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets | [1] | $ 249,875 | $ 199,123 | $ 211,653
OPEB |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 62,035 | 57,269 | $ 56,909
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 249,875 | 199,123 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension | Money market funds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 0 | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension | Large Cap Index |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 78,306 | 63,285 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension | Extended Market Index |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 16,250 | 11,827 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension | International Stock |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 50,702 | 37,353 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension | Emerging Markets |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 12,906 | 8,857 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension | Core Fixed Income |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 0 | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension | Opportunistic Income |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 0 | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension | Ultra Short Duration |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 0 | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension | High Yield Bond Fund |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 25,976 | 20,532 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension | Long Duration Fund |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 65,735 | 57,269 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 62,035 | 57,269 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB | Money market funds |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 9 | 2,237 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB | Large Cap Index |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 19,532 | 17,460 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB | Extended Market Index |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 4,114 | 3,762 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB | International Stock |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 12,997 | 10,261 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB | Emerging Markets |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 3,294 | 2,617 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB | Core Fixed Income |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 7,177 | 7,148 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB | Opportunistic Income |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 4,155 | 4,179 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB | Ultra Short Duration |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 4,082 | 3,960 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB | High Yield Bond Fund |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | 6,675 | 5,645 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | OPEB | Long Duration Fund |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined benefit plan, fair value of plan assets |  | $ 0 | $ 0 |
[1] | Includes the Company’s PEP.

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