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Financial Instruments - Narrative (Details) - Commodity Contracts [Member] $ in Thousands | 9 Months Ended
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Sep. 26, 2020 USD ($)
Derivative [Line Items] |
Deferred net gains (losses), net of tax, included in AOCI | $ 500
Cash Flow Hedging [Member] | Long [Member] |
Derivative [Line Items] |
Open option contracts written, at fair value | $ 7,000
Time period for open copper future contract purchases | 15 months
Fair value of future contracts with net gain (loss) position | $ 700
Fair Value Hedging [Member] | Short [Member] |
Derivative [Line Items] |
Fair value of future contracts with net gain (loss) position | 35
Open future contracts to sell copper | $ 600
Time period for open copper future contract sales | 6 months

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