Inventories - Summary of Inventories (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Inventory Net [Abstract]
Raw materials	$ 15,867	$ 15,819
Work in process	5,392	6,098
Finished goods	748	807
Obsolescence allowance	(2,227)	(1,907)
Total inventories	$ 19,780	$ 20,817

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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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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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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