Fair Value Measurements (Details Textual) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2013
Fair Value Measurements [Abstract]
Notional Amount of Fair Value Hedge Instruments	$ 266,395

Aggregate notional amount of all derivatives designated as a fair value hedging instrument. The notional amount relates to a number of currency units, shares, bushels, pounds, or other units specified in a derivative instrument.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Notional Amount

-URI http://asc.fasb.org/extlink&oid=6519104

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