Inventories (Details) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2013	Jan. 31, 2013	Apr. 30, 2012
Components of inventories
Finished goods	$ 110,178	$ 101,830	$ 101,104
Component parts	53,469	53,061	62,351
Work-in-process	8,619	9,463	8,586
Inventory Total	$ 172,266	$ 164,354	$ 172,041

Amount before last-in first-out (LIFO) and valuation reserves of merchandise or goods held by the entity that are readily available for sale.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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- Definition

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).

+ References

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

-Publisher FASB

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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Publisher FASB

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- Definition

Gross amount 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.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 6

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

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- Definition

Gross amount 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.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

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-Name Accounting Standards Codification

-Topic 210

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