FAIR VALUE - HIERARCHY (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Jun. 30, 2020	Sep. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other	$ 1,814	$ 1,706
Total assets at fair value	73,700	34,235
Total liabilities at fair value	70,694	76,444
Physical commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	8,177	8,624
Liabilities	39,823	40,426
Financial commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	27,499	23,904
Liabilities	14,766	35,732
Foreign currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	38	1
Liabilities	253	286
Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	15,852
Quoted Prices in Active Markets for Identical Assets, (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other	1,814	1,706
Total assets at fair value	63,335	21,734
Total liabilities at fair value	14,766	35,732
Quoted Prices in Active Markets for Identical Assets, (Level 1) | Physical commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Liabilities	0	0
Quoted Prices in Active Markets for Identical Assets, (Level 1) | Financial commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	25,349	20,028
Liabilities	14,766	35,732
Quoted Prices in Active Markets for Identical Assets, (Level 1) | Foreign currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Liabilities	0	0
Quoted Prices in Active Markets for Identical Assets, (Level 1) | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other	0	0
Total assets at fair value	10,365	12,501
Total liabilities at fair value	55,928	40,712
Significant Other Observable Inputs (Level 2) | Physical commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	8,177	8,624
Liabilities	39,823	40,426
Significant Other Observable Inputs (Level 2) | Financial commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	2,150	3,876
Liabilities	0	0
Significant Other Observable Inputs (Level 2) | Foreign currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	38	1
Liabilities	253	286
Significant Other Observable Inputs (Level 2) | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	15,852
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other	0	0
Total assets at fair value	0	0
Total liabilities at fair value	0	0
Significant Unobservable Inputs (Level 3) | Physical commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Liabilities	0	0
Significant Unobservable Inputs (Level 3) | Financial commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Liabilities	0	0
Significant Unobservable Inputs (Level 3) | Foreign currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Liabilities	0	$ 0
Significant Unobservable Inputs (Level 3) | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	0
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	36,172
Money market funds | Quoted Prices in Active Markets for Identical Assets, (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	36,172
Money market funds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0
Money market funds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$ 0