FAIR VALUE - HIERARCHY (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Mar. 31, 2021	Sep. 30, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other	$ 1,818	$ 1,840
Total assets at fair value	71,596	140,790
Total liabilities at fair value	44,196	47,217
Physical commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	5,209	7,796
Liabilities	36,506	32,517
Financial commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	13,944	18,779
Liabilities	7,661	14,593
Foreign currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	257	84
Liabilities	29	107
Quoted Prices in Active Markets for Identical Assets, (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other	1,818	1,840
Total assets at fair value	65,937	132,410
Total liabilities at fair value	7,661	14,593
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	13,751	18,279
Liabilities	7,661	14,593
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
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	5,659	8,380
Total liabilities at fair value	36,535	32,624
Significant Other Observable Inputs (Level 2) | Physical commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	5,209	7,796
Liabilities	36,506	32,517
Significant Other Observable Inputs (Level 2) | Financial commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	193	500
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	257	84
Liabilities	29	107
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
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	50,368	112,291
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	50,368	112,291
Money market funds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Money market funds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$ 0	$ 0