INVENTORIES - Summary of inventories (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Inventory Disclosure [Abstract]
Raw materials	$ 6,402	$ 6,806
Work in process	3,974	4,024
Finished goods	4,637	4,344
Spare parts and supplies	928	956
Inventories, gross	15,941	16,130
Allowance for obsolete inventory	(978)	(748)
Inventories, net	$ 14,963	$ 15,382

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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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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 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 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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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.

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