Activity of Auction Rate Securities, Fair Value Measured using Level Three Inputs (Parenthetical) (Detail) (USD $)	3 Months Ended			9 Months Ended
	Oct. 27, 2012	Jul. 28, 2012	Apr. 28, 2012	Oct. 27, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unrealized gains (losses) included in other comprehensive (loss) income	$ 6,000	$ (3,000)	$ 5,000	$ 8,000	[1]

[1] Unrealized gains of $5,000 and $6,000 occurred during the first and third quarters of fiscal 2012, respectively, and unrealized losses of $3,000 occurred during the second quarter of fiscal 2012.