Summary of Significant Accounting Policies (Inventories) (Details) - USD ($)	12 Months Ended
Dec. 29, 2018	Dec. 30, 2017
Inventory, Net [Abstract]
Finished products	$ 97,398,000	$ 101,715,000
Materials and work in process	94,161,000	81,202,000
Last-in,first-out (LIFO) allowance	(34,381,000)	(27,234,000)
Inventories, net	$ 157,178,000	$ 155,683,000
Inventory valued by the LIFO costing method	81.40%	83.36%
Effect of LIFO inventory, decrease (increase) in cost of goods sold	$ (500,000)	$ 0

The effect of liquidating LIFO (last in first out) inventory layers on income.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SAB Topic 11.F)
-URI http://asc.fasb.org/extlink&oid=27011343&loc=d3e100079-122729

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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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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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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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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The aggregate carrying amount as of the balance sheet date of items held by the entity which are partially completed at the time of measurement and unprocessed items that will go through the production process and become part of the final product. Includes supplies used directly or indirectly in the manufacturing or production process. This element may be used when the reporting entity combines work in process and raw materials into an aggregate amount.

+ References

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The percentage of LIFO (last in first out) inventory to total inventory as of the balance sheet date if other than 100 percent.

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