Recent Accounting Pronouncements - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
Oct. 31, 2013	Oct. 31, 2013
Accumulated Other Comprehensive Income Loss [Line Items]
Reclassification amount from other comprehensive income	$ 43,000	$ 43,000

Amount after tax of reclassification adjustments of other comprehensive income (loss).

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration