Derivative Instruments and Hedging Activities (Details) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 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]	Mar. 31, 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]
Derivatives, Fair Value [Line Items]
Other current assets: gain positions		$ 961,000	$ 85,000
Other current assets: loss positions		(170,000)	(25,000)
Other current liability: gain positions				12,000	339,000
Other current liability: loss positions				(16,000)	(1,078,000)
Net fair value of realized gains and losses of cash flow hedges that will be reclassified into earnings	803,000
Open future contracts to purchase copper	25,600,000
Time period for open copper future contract (in months)	21M
Gain on fair value of future contracts	$ 787,000