EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
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