Inventories by Major Categories (Detail) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Schedule of Inventory [Line Items]
Raw materials	$ 12,906,713	$ 9,371,850
Work in progress	419,695	556,816
Inventories	17,844,405	15,502,246
Copper and CCA wire
Schedule of Inventory [Line Items]
Other inventory	2,947,584	2,925,769
Copper rod and anode
Schedule of Inventory [Line Items]
Other inventory	$ 1,570,413	$ 2,647,811