Inventories (Details) (USD $) In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013
Inventory Disclosure [Abstract]
Raw materials	$ 40,649us-gaap_InventoryRawMaterials	$ 31,864us-gaap_InventoryRawMaterials
Work-in-process	19,976us-gaap_InventoryWorkInProcess	16,880us-gaap_InventoryWorkInProcess
Finished goods	57,913us-gaap_InventoryFinishedGoods	57,983us-gaap_InventoryFinishedGoods
Supplies and other	126us-gaap_OtherInventorySupplies	118us-gaap_OtherInventorySupplies
LIFO reserve	(14,457)us-gaap_InventoryLIFOReserve	(13,626)us-gaap_InventoryLIFOReserve
Inventories	$ 104,207us-gaap_InventoryNet	$ 93,219us-gaap_InventoryNet

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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://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 6

-Subparagraph a

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-Subparagraph (SX 210.5-02.6(a)(1))

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Amount of difference between inventory at lower of LIFO cost or market and inventory at lower of other inventory accounting method cost or market, for example, but not limited to, FIFO or average cost.

+ References

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Topic 330

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

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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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-Publisher SEC

-Name Regulation S-X (SX)

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Amount before valuation and LIFO reserves of other supplies used within the manufacturing or production process expected to be consumed within one year or operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

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