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DERIVATIVES AND RISK MANAGEMENT - Commodity Contract Commitments (Details) | 12 Months Ended
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Aug. 31, 2018 t
Aluminum | Long |
Derivative [Line Items] |
Commodity contract commitments | 3,975
Aluminum | Short |
Derivative [Line Items] |
Commodity contract commitments | 550
Copper | Long |
Derivative [Line Items] |
Commodity contract commitments | 1,633
Copper | Short |
Derivative [Line Items] |
Commodity contract commitments | 5,817

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