Fair Value Hierarchy for Financial Assets (Cash Equivalents and Investments) Measured at Fair Value on a Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Jul. 28, 2012	Jan. 28, 2012	Jul. 30, 2011	Jan. 29, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 696,077	$ 719,545	$ 389,299	$ 667,593
Short-term investments	5,995	25,499	124,697
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	696,077	719,545	389,299
Short-term investments	5,995	25,499	124,697
Long-term investments	254	847	648
Total	702,326	745,891	514,644
Fair Value, Measurements, Recurring | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	623,277	548,728	287,753
Fair Value, Measurements, Recurring | Money-market
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	44,789	131,785	74,387
Fair Value, Measurements, Recurring | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	5,000	29,998	23,996
Short-term investments			9,997
Fair Value, Measurements, Recurring | Treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	23,011	9,034	3,163
Short-term investments	5,995	19,999	76,262
Fair Value, Measurements, Recurring | ARS Call Option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term investments	254	847	648
Fair Value, Measurements, Recurring | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments			16,111
Fair Value, Measurements, Recurring | Term Loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments			15,427
Fair Value, Measurements, Recurring | Quoted Market Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	696,077		389,299
Short-term investments	5,995		117,797
Total	702,072		507,096
Fair Value, Measurements, Recurring | Quoted Market Prices in Active Markets for Identical Assets (Level 1) | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	623,277		287,753
Fair Value, Measurements, Recurring | Quoted Market Prices in Active Markets for Identical Assets (Level 1) | Money-market
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	44,789		74,387
Fair Value, Measurements, Recurring | Quoted Market Prices in Active Markets for Identical Assets (Level 1) | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	5,000		23,996
Short-term investments			9,997
Fair Value, Measurements, Recurring | Quoted Market Prices in Active Markets for Identical Assets (Level 1) | Treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	23,011		3,163
Short-term investments	5,995		76,262
Fair Value, Measurements, Recurring | Quoted Market Prices in Active Markets for Identical Assets (Level 1) | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments			16,111
Fair Value, Measurements, Recurring | Quoted Market Prices in Active Markets for Identical Assets (Level 1) | Term Loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments			15,427
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments			6,900
Long-term investments	254		648
Total	254		7,548
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | ARS Call Option
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term investments	254		648
Fair Value, Measurements, Recurring | ARS | State and local government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments		5,500	6,900
Fair Value, Measurements, Recurring | ARS | Significant Unobservable Inputs (Level 3) | State and local government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments			$ 6,900