Commitments and Contingencies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Oct. 31, 2013	Jan. 31, 2013
Debt Instrument [Line Items]
Long-term debt, maturity date	March 2016
Long-term debt	$ 410,042	$ 410,042
Operating Lease Obligations [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Operating lease agreements expire period	2022
Operating Lease Obligations [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Operating lease agreements expire period	2013

Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant