Fire At Bus Production Facility (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Apr. 30, 2011	Apr. 30, 2012	Apr. 30, 2011
Fire At Bus Production Facility [Abstract]
Amount deductible per the policy		$ 5,000
Insurance proceeds received for losses incurred			9,566
Business interruption portion of insurance proceeds			5,378
Clean up and other costs			915
Gain on business interruption insurance recovery	$ 1,818		$ 8,651

The net amount (to the extent disclosed within this portion of the income statement) by which an insurance settlement exceeds incremental costs incurred from the event causing an interruption of business, plus the insurance award for earnings lost from the event, such as a natural catastrophe, explosion or fire.

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

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 01-13

-Paragraph 7

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 225

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6365675&loc=d3e16285-107787

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration