Derivative Instruments and Hedging Activities - Outstanding commodity hedge contracts (Detail)	Jun. 30, 2015 T lb	Sep. 30, 2014 T lb	Jun. 30, 2014 T lb
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Pounds of Copper | lb	8,479,000	9,536,000	11,230,000
Metric Tons of Lead	10,892	5,200	0
Metric Tons of Aluminum	4,365	0	0
Metric Tons of Tin	2,836	2,070	636