Inventories - Summary of Inventories (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Finished goods	$ 30,936	$ 32,986
Raw materials	22,419	19,432
Total FIFO (first-in,first-out) inventories	53,355	52,418
Reserve to adjust inventories to LIFO value	(20,070)	(20,070)
Total LIFO inventories	$ 33,285	$ 32,348

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- Definition

Amount before valuation and LIFO reserves of completed merchandise or goods expected to be sold within one year or operating cycle, if longer.

+ References

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-Publisher FASB
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- Definition

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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- Definition

Amount by which inventory stated at last-in first-out (LIFO) is less than (in excess of) inventory stated at other inventory cost methods.

+ References

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-Publisher FASB
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- Definition

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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The amount of LIFO (last in first out) inventory present at the reporting date when inventory is also valued using different valuation methods.

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