Inventories - Components of Inventories (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 81,849	$ 76,732
Work in process	90,494	84,561
Finished goods	105,425	110,388
Inventory Reserves	(33,936)	(34,174)
Total	$ 243,832	$ 237,507

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

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Amount of valuation reserve for inventory.

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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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