Derivatives (Details 1)	Mar. 31, 2015 lb	Dec. 31, 2014 lb
Designated as Hedging Instrument [Member] | Copper [Member]
Derivative [Line Items]
Nonmonetary notional amount	24,900,000	29,400,000
Not Designated as Hedging Instrument [Member] | Copper [Member]
Derivative [Line Items]
Nonmonetary notional amount	2,500,000	2,900,000
Not Designated as Hedging Instrument [Member] | Aluminum [Member]
Derivative [Line Items]
Nonmonetary notional amount	2,500,000	2,200,000