Summary of the Components of the Special Charges (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2012	Jul. 31, 2011
Disclosure Summary Of Components Of Special Charges [Abstract]
Employee severance and related costs	$ 1,029	$ 1,207	$ 2,017	$ 2,354
Other costs	478	470	637	3,870
Total special charges	$ 1,507	$ 1,677	$ 2,654	$ 6,224

The charge against earnings in the period, comprised of costs associated with restructuring activities not otherwise specified in the taxonomy pursuant to a duly authorized plan, excluding a discontinued operation as defined by generally accepted accounting principles. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, but excludes costs associated with the retirement of a long-lived asset and severance costs associated with established compensation plans.

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The charge against earnings in the period for known and estimated costs of termination benefits provided to current employees that are involuntarily terminated under a benefit arrangement associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, excluding costs or losses pertaining to an entity newly acquired in a business combination or a discontinued operation as defined by generally accepted accounting principles and costs associated with one-time termination benefits.

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