Summary of the Components of the Special Charges (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Apr. 30, 2013	Apr. 30, 2012
Disclosure Summary Of Components Of Special Charges [Abstract]
Employee severance and related costs	$ 2,079	$ 988
Other costs	4	159
Special charges	$ 2,083	$ 1,147

Amount charged against earnings in the period for incurred and estimated costs associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, excluding asset retirement obligations.

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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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