SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Detail) - USD ($) $ in Thousands		12 Months Ended
		Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period		$ 74,261	$ 53,441	$ 54,987
Charged to Costs and Expenses		266,945	212,660	162,817
Deductions	[1]	245,520	191,840	164,363
Balance at End of Period		95,686	74,261	53,441
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period		1,346	1,074	642
Charged to Costs and Expenses		682	515	584
Deductions	[1]	836	243	152
Balance at End of Period		1,192	1,346	1,074
Reserve for sales allowances
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	[2]	72,915	52,367	54,345
Charged to Costs and Expenses	[2]	266,263	212,145	162,233
Deductions	[1],[2]	244,684	191,597	164,211
Balance at End of Period	[2]	$ 94,494	$ 72,915	$ 52,367

[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.