SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2015		Jan. 31, 2014		Jan. 31, 2013
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 54,987		$ 45,947		$ 34,436
Charged to Costs and Expenses	162,817		141,950		114,622
Deductions	164,363	[1]	132,910	[1]	103,111	[1]
Balance at End of Period	53,441		54,987		45,947
Allowance for doubtful accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	642		1,189		1,483
Charged to Costs and Expenses	584		355		206
Deductions	152	[1]	902	[1]	500	[1]
Balance at End of Period	1,074		642		1,189
Reserve for sales allowances
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	54,345	[2]	44,758	[2]	32,953	[2]
Charged to Costs and Expenses	162,233	[2]	141,595	[2]	114,416	[2]
Deductions	164,211	[1],[2]	132,008	[1],[2]	102,611	[1],[2]
Balance at End of Period	$ 52,367	[2]	$ 54,345	[2]	$ 44,758	[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.