Discontinued Operations - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended
	Oct. 20, 2013	Oct. 31, 2013	Apr. 30, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of bus business		$ 100,000
Proceeds from sale of bus business, net of cash sold		97,677
Sale of bus business, cash sold		2,323
Discontinued operation, amounts due from ASV	6,006
Discontinued operation, total amounts due from ASV	8,329
Pre-tax gain on sale of business		7,825
Disposition of ambulance net assets			12,051
Gain (loss) recognized on sale of assets			0
Impact of indemnification to tax expenses		$ 1,883