Inventories (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Mar. 31, 2012
Inventory Disclosure [Abstract]
Raw materials	$ 61,186	$ 59,252
Work-in-process	18,216	18,952
Finished goods	54,115	49,315
Inventory, Gross	133,517	127,519
LIFO cost less than FIFO cost	(21,466)	(19,464)
Net inventories	$ 112,051	$ 108,055

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Carrying amount as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

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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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Reflects the difference between (a) inventory at the lower of LIFO cost or market and (b) inventory at replacement cost or at the lower of some acceptable inventory accounting method (such as FIFO or average cost), or market. If material, reflects an excess of replacement or current cost over stated LIFO value parenthetically on the balance sheet or in a note to the financial statements.

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Carrying amount (lower of cost or market) as of the balance sheet date of inventories less all valuation and other allowances. Excludes noncurrent inventory balances (expected to remain on hand past one year or one operating cycle, if longer).

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Carrying amount as of the balance sheet date of unprocessed items to be consumed in the manufacturing or production process. Also includes purchased parts that will be used as components of a finished product.

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Carrying amount as of the balance sheet date of merchandise or goods which are partially completed, are generally comprised of raw materials, labor and factory overhead costs, and which require further materials, labor and overhead to be converted into finished goods, and which generally require the use of estimates to determine percentage complete and pricing.

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