Operating Lease and Asset Retirement Obligations - Narrative (Detail) (USD $)	12 Months Ended
Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Schedule of Operating Leases [Line Items]
Rent expense under operating leases, including insignificant amounts of contingent rental payments	$ 23,873,000	$ 28,924,000	$ 29,106,000

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717

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