Derivatives and Risk Management (Details)	Nov. 30, 2011 MT
Aluminum [Member] | Long [Member]
Commodity Contract Commitments [Abstract]
Commodity Contract Commitments	5,175
Aluminum [Member] | Short [Member]
Commodity Contract Commitments [Abstract]
Commodity Contract Commitments	3,225
Copper [Member] | Long [Member]
Commodity Contract Commitments [Abstract]
Commodity Contract Commitments	848
Copper [Member] | Short [Member]
Commodity Contract Commitments [Abstract]
Commodity Contract Commitments	5,636
Zinc [Member] | Long [Member]
Commodity Contract Commitments [Abstract]
Commodity Contract Commitments	36
Natural Gas [Member] | Long [Member]
Commodity Contract Commitments [Abstract]
Commodity Contract Commitments	160,000