Schedule I Parent Only Balance Sheets, Statements Of Earnings And Cash Flows (Cash Flows) (Parenthetical) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Schedule I Parent Only Balance Sheets, Statements Of Earnings And Cash Flows [Abstract]
Issuance costs	$ 62	$ 300	$ 18

The cash outflow for cost incurred directly with the issuance of an equity security.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 18, 19, 20

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3291-108585

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration