Acquisitions - Additional Information (Detail) - USD ($) $ in Thousands			3 Months Ended	6 Months Ended		12 Months Ended
	May. 01, 2015	Jan. 05, 2015	Jul. 31, 2015	Jan. 31, 2016	Jan. 31, 2015	Jul. 31, 2015
Business Acquisition [Line Items]
Payment to acquire business, net					$ 49,265
Postle Operating, LLC
Business Acquisition [Line Items]
Payment to acquire business, net	$ 144,048
Asset purchase agreement date						May 01, 2015
Amortizable intangible assets, weighted average useful life	12 years 3 months 18 days
Cash on hand at the acquisition date	$ 2,963
Cruiser RV, LLC and DRV, LLC
Business Acquisition [Line Items]
Payment to acquire business, net		$ 47,523	$ 47,523
Asset purchase agreement date		Dec. 31, 2014
Amortizable intangible assets, weighted average useful life		13 years 10 months 24 days
Payment to acquire business		$ 47,412
Purchase price adjustment			1,173
Cash on hand at the acquisition date		1,062	$ 1,062			$ 1,062
Initial payment to acquire business		$ 46,350
Customer Relationships
Business Acquisition [Line Items]
Intangible assets amortization period	12 years
Amortizable intangible assets, amortization method				Accelerated cash flow basis
Trademarks
Business Acquisition [Line Items]
Intangible assets amortization period	15 years	20 years		18 years
Amortizable intangible assets, amortization method				Straight-line basis
Backlog
Business Acquisition [Line Items]
Intangible assets amortization period	42 days	42 days
Amortizable intangible assets, amortization method				Straight-line basis
Dealer Networks
Business Acquisition [Line Items]
Intangible assets amortization period		12 years
Amortizable intangible assets, amortization method				Accelerated cash flow basis