Inventories (Schedule Of Inventories) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Inventory, Net [Abstract]
Finished goods	$ 17,559	$ 14,953
Work-in-process	10,089us-gaap_InventoryWorkInProcess	7,750us-gaap_InventoryWorkInProcess
Raw materials	25,227	24,477
Stores, supplies and other	21,433us-gaap_InventorySuppliesNetOfReserves	23,483us-gaap_InventorySuppliesNetOfReserves
Total	$ 74,308us-gaap_InventoryNet	$ 70,663us-gaap_InventoryNet

Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

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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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Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of unprocessed items to be consumed in the manufacturing or production process.

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Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of products used directly or indirectly in the manufacturing or production process, which may or may not become part of the final product. May also include items used in the storage, presentation or transportation of physical goods.

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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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