INVENTORIES (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
INVENTORIES
Parts and raw materials	$ 28,271	$ 24,910
Work-in-process	7,467	5,984
Finished goods	8,327	6,075
Inventory, gross	44,065	36,969
Less reserves	(4,446)	(4,401)
Inventories	$ 39,619	$ 32,568

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