Components of Amortizable Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended		6 Months Ended
	Oct. 31, 2013	Aug. 30, 2013	Jan. 31, 2014	Jul. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Cost			$ 142,852	$ 127,472
Accumulated Amortization			35,783	29,719
Dealer Networks
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life in Years	12 years	8 years	9 years
Cost			77,600	67,000
Accumulated Amortization			22,873	19,121
Non-Compete Agreements
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life in Years		2 years	2 years
Cost			4,260	4,130
Accumulated Amortization			2,815	2,375
Trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life in Years	20 years	20 years	21 years
Cost			38,342	35,042
Accumulated Amortization			4,612	3,843
Design Technology And Other Intangibles
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life in Years			11 years
Cost			22,650	21,300
Accumulated Amortization			$ 5,483	$ 4,380