Investments - Schedule of Outstanding Foreign Currency Derivative Contracts Related Primarily to Intercompany Receivables and Payables (Detail) (USD $) In Thousands, unless otherwise specified	Oct. 31, 2014	Jan. 31, 2014
Derivative [Line Items]
Fair value of foreign currency derivative contracts	$ (891)	$ (203)
Foreign currency derivative contracts
Derivative [Line Items]
Notional amount of foreign currency derivative contracts	$ 661,238	$ 563,060

Fair value as of the balance sheet date of foreign currency derivative assets, net of foreign currency derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized on the balance sheet.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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