Valuation and Qualifying Accounts and Reserves (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Allowance for shrinkage and inventory obsolescence [Member]
Summary of valuation and qualifying accounts and reserves
Balance at the beginning of period	$ 5,348	$ 6,374	$ 5,288
Additions charged to costs and expenses	8,478	10,545	13,064
Deductions for write-offs	(9,662)	(11,571)	(11,978)
Balance at end of period	4,164	5,348	6,374
Allowance for costs of inventory returns [Member]
Summary of valuation and qualifying accounts and reserves
Balance at the beginning of period	724	833	891
Additions charged to costs and expenses	3,796	4,152	4,388
Deductions for write-offs	(3,707)	(4,261)	(4,446)
Balance at end of period	$ 813	$ 724	$ 833