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DERIVATIVES AND RISK MANAGEMENT - Commodity Contract Commitments (Details)	12 Months Ended
	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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