Schedule II-Valuation and Qualifying Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2014		Jan. 31, 2013		Jan. 31, 2012
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 45,947		$ 34,436		$ 32,174
Charged to Costs and Expenses	141,950		114,622		78,407
Deductions	132,910	[1]	103,111	[1]	76,145	[1]
Balance at End of Period	54,987		45,947		34,436
Allowance for doubtful accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	1,189		1,483		1,350
Charged to Costs and Expenses	355		206		643
Deductions	902	[1]	500	[1]	510	[1]
Balance at End of Period	642		1,189		1,483
Reserve for sales allowances
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	44,758	[2]	32,953	[2]	30,824	[2]
Charged to Costs and Expenses	141,595	[2]	114,416	[2]	77,764	[2]
Deductions	132,008	[1],[2]	102,611	[1],[2]	75,635	[1],[2]
Balance at End of Period	$ 54,345	[2]	$ 44,758	[2]	$ 32,953	[2]

[1] Accounts written off as uncollectible, net of recoveries.

[2] See Note A in the accompanying Notes to Consolidated Financial Statements for a description of sales allowances.