Valuation and Qualifying Accounts and Reserves (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Allowance for shrinkage and inventory obsolescence
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at the beginning of period	$ 4,164	$ 5,348	$ 6,374
Additions charged to costs and expenses	8,992	9,079	11,711
Deductions for write-offs	(9,243)	(10,263)	(12,737)
Balance at end of period	3,913	4,164	5,348
Allowance for costs of inventory returns
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at the beginning of period	813	724	833
Additions charged to costs and expenses	3,340	3,796	4,152
Deductions for write-offs	(3,556)	(3,707)	(4,261)
Balance at end of period	$ 597	$ 813	$ 724