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EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category - USD ($) $ in Thousands | Sep. 30, 2018 | Sep. 30, 2017
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EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | $ 150,634 | $ 150,822
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 82,520 | 82,099
Significant Other Observable Inputs (Level 2) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 68,114 | 68,723
Significant Unobservable Inputs (Level 3) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 0 | 0
Cash and equivalents [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 27,209 | 27,156
Cash and equivalents [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 27,209 | 27,156
Cash and equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 0 | 0
Cash and equivalents [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 0 | 0
Debt instruments [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 14,269 | 14,520
Debt instruments [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 14,269 | 14,520
Debt instruments [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 0 | 0
Debt instruments [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 0 | 0
Equity securities [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 41,042 | 40,423
Equity securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 41,042 | 40,423
Equity securities [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 0 | 0
Equity securities [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 0 | 0
Commingled funds [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 62,088 | 62,907
Commingled funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 0 | 0
Commingled funds [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 62,088 | 62,907
Commingled funds [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 0 | 0
Limited partnerships and hedge fund investments [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 6,026 | 5,816
Limited partnerships and hedge fund investments [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 0 | 0
Limited partnerships and hedge fund investments [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | 6,026 | 5,816
Limited partnerships and hedge fund investments [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items] |  |
Defined Benefit Plan, Plan Assets, Amount | $ 0 | $ 0

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