Inventories (Details) - USD ($) $ in Thousands	Sep. 25, 2020	Dec. 27, 2019
Inventory, Net [Abstract]
Finished products and components	$ 135,281	$ 132,128
Products and components in various stages of completion	84,588	86,957
Raw materials and purchased components	127,151	117,026
Inventory gross	347,020	336,111
Reduction to LIFO cost	(63,307)	(62,878)
Total	$ 283,713	$ 273,233

Amount before valuation and LIFO reserves of completed merchandise or goods expected to be sold within one year or operating cycle, if longer.

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Gross amount, as of the balance sheet date, of merchandise, goods, commodities, or supplies held for future sale or to be used in manufacturing, servicing or production process.

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Amount by which inventory stated at last-in first-out (LIFO) is less than (in excess of) inventory stated at other inventory cost methods.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Gross amount of unprocessed materials to be used in manufacturing or production process and supplies that will be consumed.

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Amount before valuation and LIFO reserves of merchandise or goods in the production process expected to be completed within one year or operating cycle, if longer.

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