EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 145,319	$ 150,634
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	104,246	82,520
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	32,297	68,114
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	8,776	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	2,791	27,209
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	2,791	27,209
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	3,178	14,269
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	182	14,269
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	2,996	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	72,517	41,042
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	72,517	41,042
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	8,776	62,088
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	0	62,088
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	8,776	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	18,569	6,026
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	18,569	6,026
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
Other Security Investments [Member]
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items]
Defined Benefit Plan, Plan Assets, Amount	2,072
Other Security 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	1,348
Other Security 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	724
Other Security 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
US Government Agencies Debt Securities [Member]
EMPLOYEE BENEFIT PLANS (Details) - Pension and post-retirement plan assets by asset category [Line Items]
Defined Benefit Plan, Plan Assets, Amount	37,416
US Government Agencies Debt 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	27,408
US Government Agencies Debt 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	10,008
US Government Agencies Debt 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