Derivative Instruments and Hedging Activities (Details) (USD $)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012 Other Current Assets [Member] Commodity contracts [Member] Designated as Hedging Instrument [Member]	Dec. 31, 2011 Other Current Assets [Member] Commodity contracts [Member] Designated as Hedging Instrument [Member]	Jun. 30, 2012 Other Current Liabilities [Member] Commodity contracts [Member] Designated as Hedging Instrument [Member]	Dec. 31, 2011 Other Current Liabilities [Member] Commodity contracts [Member] Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities [Abstract]
Net fair value of cash flow hedges whose realized gains or losses would be reclassified into earnings	$ 133,000
Open future contracts	18,000,000
Time period for open copper future contract (in months)	18 months
Fair value of future contracts with loss position	216,000
Derivatives, Fair Value [Line Items]
Other current assets: gain positions		87,000	85,000
Other current assets: loss positions		(25,000)	(25,000)
Other current liability: gain positions				213,000	339,000
Other current liability: loss positions				$ (491,000)	$ (1,078,000)