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Financial Instruments - Additional Information (Details) - USD ($)
$ in Thousands
6 Months Ended
Jun. 30, 2018
Dec. 30, 2017
Derivative [Line Items]    
Restricted cash in other current assets as collateral related to open derivative contracts $ 2,100 $ 5,300
Commodity Contracts [Member]    
Derivative [Line Items]    
Deferred net losses, net of tax, included in AOCI 215  
Cash Flow Hedging [Member] | Commodity Contracts [Member] | Long [Member]    
Derivative [Line Items]    
Open option contracts written, at fair value $ 48,200  
Time period for open copper future contract purchases 15 months  
Fair value of future contracts with (loss) gain position $ (639)  
Fair Value Hedging [Member] | Commodity Contracts [Member] | Short [Member]    
Derivative [Line Items]    
Fair value of future contracts with (loss) gain position 8  
Open future contracts to sell copper $ 200  
Time period for open copper future contract sales 3 months