Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Mar. 31, 2019
Inventory [Line Items]
Raw materials	$ 93,778	$ 88,786
Work-in-process	24,819	32,547
Finished goods	35,204	40,523
At cost - FIFO basis:	153,801	161,856
LIFO cost less than FIFO cost	(18,352)	(15,593)
Net inventories	$ 135,449	$ 146,263

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

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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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