Credit Risk Assessment for Long-term Receivables (Detail) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2014	Jan. 31, 2014
Accounts and Financing Receivable [Line Items]
Term receivables, long-term	$ 264,843	$ 270,365
S&P credit rating, AAA+ through BBB-
Accounts and Financing Receivable [Line Items]
Term receivables, long-term	177,508	180,113
S&P credit rating, BB+ and lower
Accounts and Financing Receivable [Line Items]
Term receivables, long-term	21,657	29,654
S&P credit rating
Accounts and Financing Receivable [Line Items]
Term receivables, long-term	199,165	209,767
Internal Credit Rating
Accounts and Financing Receivable [Line Items]
Term receivables, long-term	$ 65,678	$ 60,598

Amount due from customers or clients, more than one year from the balance sheet date, for goods or services that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.17)

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Article 5

Name:	us-gaap_AccountsReceivableNetNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant