Severance and Reorganization - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Apr. 30, 2013
Reorganization Items [Line Items]
One-time severance and reorganization charge	$ 1,882	$ 1,882	$ 1,793	$ 3,709
Liability associated with severance and reorganization	$ 680			$ 680

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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