Fair Value Measurements - Changes in Fair Value (Detail) (Fair Value, Measurements, Recurring [Member], USD $)
In Thousands, unless otherwise specified
3 Months Ended
Apr. 28, 2012
Apr. 30, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Balance, Level 3 securities, beginning of year $ 11,220 $ 8,586
Transfers into Level 3   2,787
Sales of Level 3 securities (25) (25)
Balance, Level 3 securities, end of quarter 11,195 11,348
Auction-rate securities [Member]
   
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Balance, Level 3 securities, beginning of year 11,220 8,586
Transfers into Level 3   2,787 [1]
Sales of Level 3 securities (25) (25)
Balance, Level 3 securities, end of quarter $ 11,195 $ 11,348
[1] Transferred from Level 2 to Level 3 due to lack of observable market data due to reduction in market activity. The Company's policy is to recognize transfers in and transfers out as of the beginning of the reporting period in which the transfer occurred.