Components of Amortizable Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012 Year	Jul. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Cost	$ 136,626	$ 138,010
Accumulated Amortization	22,399	12,755
Dealer Networks
Finite-Lived Intangible Assets [Line Items]
Weighted Average Years Remaining Life	11
Cost	72,230	72,230
Accumulated Amortization	13,343	6,154
Non-Compete Agreements
Finite-Lived Intangible Assets [Line Items]
Weighted Average Years Remaining Life	3
Cost	6,321	6,851
Accumulated Amortization	3,678	3,300
Trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted Average Years Remaining Life	23
Cost	36,775	36,669
Accumulated Amortization	2,522	1,008
Design Technology And Other Intangibles
Finite-Lived Intangible Assets [Line Items]
Weighted Average Years Remaining Life	13
Cost	21,300	22,260
Accumulated Amortization	$ 2,856	$ 2,293