Derivative Instruments and Hedging Activities (Details) (USD $)	3 Months Ended
	Mar. 28, 2015		Dec. 27, 2014
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Assets fair value	$ 839,000	[1]	$ 95,000	[1]
Liabilities fair value	(2,749,000)	[1]	(1,825,000)	[1]
Commodity Contracts [Member] | Cash Flow Hedging [Member] | Long [Member]
Derivatives, Fair Value [Line Items]
Open future contracts to purchase copper	32,400,000
Time period for open copper future contract purchases	9 months
Fair value of future contracts with gain (loss) position	354,000
Commodity Contracts [Member] | Fair Value Hedging [Member] | Short [Member]
Derivatives, Fair Value [Line Items]
Open future contracts to sell copper	20,100,000
Time period for open copper future contract sales	4 months
Fair value of future contracts with gain (loss) position	181,000
Other Current Asset [Member] | Commodity Contracts [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Other current assets: Gain positions	941,000		99,000
Other current assets: Loss positions	(102,000)		(4,000)
Other Current Asset [Member] | Foreign Currency Contracts [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Other current assets: Gain positions	0		0
Other Assets [Member] | Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Other assets: Gain positions	0		0
Other Current Liabilities [Member] | Commodity Contracts [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Other current liability: Gain positions	310,000		15,000
Other current liability: Loss positions	(614,000)		(832,000)
Other Current Liabilities [Member] | Foreign Currency Contracts [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Other current liability: Loss positions	(9,000)		(81,000)
Other Liabilities [Member] | Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Other liabilities: Loss positions	$ (2,436,000)		$ (927,000)

[1] Does not include the impact of cash collateral received from or provided to counterparties.