Severance and Other Restructuring Costs - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Jul. 31, 2013 Employees	Jul. 31, 2013 Employees
Restructuring And Related Activities [Abstract]
Severance and restructuring charges	$ 0.6	$ 0.8
Number of employees	11	19

The number of positions eliminated during the period as a result of restructuring activities.

No definition available.

Name:	us-gaap_RestructuringAndRelatedCostNumberOfPositionsEliminated
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration