Term Receivable and Trade Accounts Receivable Balances (Detail) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2013	Jan. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable, net	$ 367,389	$ 412,245
Term receivables, long-term	228,425	250,497
Trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable, net	125,969	178,351
Term receivables, short-term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable, net	$ 241,420	$ 233,894

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) 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 210.5-02.3-4)

-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

-Subparagraph a(1)

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 4

-Article 5

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