Amount of potential cash payments that could result from the contingent consideration arrangement.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_BusinessAcquisitionContingentConsiderationPotentialCashPayment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Acquisitions of and Investments in Businesses and Technologies (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended		3 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Apr. 30, 2012 Ranchview [Member]	Jan. 31, 2013 Ranchview [Member]	Nov. 30, 2009 Ranchview [Member]
Business Acquisition [Line Items]
Business Acquisition, Contingent Consideration, Potential Cash Payment					$ 4,000
Cash paid to settle outstanding contingent consideration				1,841
Gain on acquisition-related contingent liability settlement	$ (508)	$ 0	$ 508