Employee Benefit Plan (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009
United States Defined Contribution Plan
Defined Contribution Plans [LineItem]
Recognized Deferred Compensation expenses	$ 0.4	$ 0.5	$ 0.5
Defined Contribution Plan, Contributions by Employer, Percentage	20.00%
Maximum Employer Contribution on employees salary deferral	15.00%
Uk Based Defined Contribution Plans
Defined Contribution Plans [LineItem]
Recognized Deferred Compensation expenses	$ 0.2	$ 0.3	$ 0.7
Defined Contribution Plan, Contributions by Employer, Percentage	5.00%

The amount of the cost recognized during the period for defined contribution plans.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 11

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 70

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration