Discontinued Operations - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	0 Months Ended		3 Months Ended	12 Months Ended
	Feb. 19, 2014	Oct. 21, 2013	Apr. 30, 2013	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of bus business		$ 100,000		$ 105,043
Discontinued operation, amounts collected from ASV	5,043
Pre-tax gain on sale of business				7,079
Third quarter impairment				0	0	0
Disposition of ambulance net assets			12,051
Gain (loss) recognized on sale of assets			0
Impact of indemnification to tax expenses				1,883
Buses
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill fair value				0
Third quarter impairment			6,810
Impairment of goodwill and intangible assets			11,525
Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Amortizable intangible assets impairment charge			$ 4,715