Acquisitions - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended			1 Months Ended				3 Months Ended	12 Months Ended			12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		5 Months Ended	12 Months Ended		12 Months Ended		12 Months Ended			12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010	Sep. 16, 2010 Towable Holdings, Inc.	Oct. 31, 2011 Towable Holdings, Inc.	Jul. 31, 2011 Towable Holdings, Inc.	Apr. 30, 2011 Towable Holdings, Inc.	Oct. 31, 2011 Heartland Recreational Vehicles, LLC,	Jul. 31, 2012 Heartland Recreational Vehicles, LLC, Year	Jul. 31, 2011 Heartland Recreational Vehicles, LLC,	Sep. 16, 2010 Heartland Recreational Vehicles, LLC,	Jul. 31, 2012 Heartland Recreational Vehicles, LLC, Design Technology Assets Year	Sep. 16, 2010 Heartland Recreational Vehicles, LLC, Design Technology Assets	Jul. 31, 2012 Heartland Recreational Vehicles, LLC, Trademarks Year	Sep. 16, 2010 Heartland Recreational Vehicles, LLC, Trademarks	Jul. 31, 2012 Heartland Recreational Vehicles, LLC, Non-Compete Agreements Year	Sep. 16, 2010 Heartland Recreational Vehicles, LLC, Non-Compete Agreements	Jul. 31, 2012 Heartland Recreational Vehicles, LLC, Backlog Week	Sep. 16, 2010 Heartland Recreational Vehicles, LLC, Backlog	Jul. 31, 2012 Heartland Recreational Vehicles, LLC, Dealer Networks Year	Sep. 16, 2010 Heartland Recreational Vehicles, LLC, Dealer Networks	Jul. 31, 2010 SJC Industries Corp.	Jul. 31, 2012 SJC Industries Corp. Year	Mar. 01, 2010 SJC Industries Corp.	Jul. 31, 2012 SJC Industries Corp. Design Technology Assets Year	Mar. 01, 2010 SJC Industries Corp. Design Technology Assets	Jul. 31, 2012 SJC Industries Corp. Trademarks Year	Jul. 31, 2012 SJC Industries Corp. Non-Compete Agreements Year	Mar. 01, 2010 SJC Industries Corp. Non-Compete Agreements	Jul. 31, 2012 SJC Industries Corp. Dealer Networks Year	Mar. 01, 2010 SJC Industries Corp. Dealer Networks
Business Acquisition [Line Items]
Cash paid for acquisition				$ 99,562	$ 170	$ 99,732																		$ 19,756
Shares issued of unregistered common stock				4,300,000
Value of shares issued of unregistered common stock				90,531
Acquisition, transaction costs							1,826
Common stock transfer restriction period	4 years
Business acquisition purchase price allocation adjustments to reflect finalization of indemnification matters resulting in increase to goodwill								757
Capital lease obligations assumed											429
Weighted average useful life on amortized intangible assets, years									14.9														13.4
Amortization period, Minimum years												10
Amortizable intangible assets being amortized using straight line method over, maximum years												15
Amortizable intangible assets using straight line method over														25		5		3		12					5		20	5		14
Goodwill acquired that remains deductible for tax purposes											11,600
Net sales										365,389												13,218
Net income before tax	180,691	152,627	171,393							13,132
One Time Costs Related to Step-up Of Finished Goods Inventory										746
Amortizable intangible assets													21,300		25,200		4,130		690		67,000					270			120		5,230
Ongoing amortization costs related to heartland acquisition										8,563
Acquired total voting interest through business acquisition																								100.00%
Future cash obligations																								325
Total purchase price agreement																								$ 20,081