Components of Net Postretirement Medical Expense (credit) (Detail) (Other Postretirement Benefit Plans, Defined Benefit, USD $) In Thousands	3 Months Ended		6 Months Ended
	Jul. 30, 2011	Jul. 31, 2010	Jul. 30, 2011	Jul. 31, 2010
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Interest expense on accumulated postretirement benefit obligation	$ 15	$ 17	$ 30	$ 35
Prior service cost amortization		(380)		(760)
Net amortization and deferral	51	130	102	261
Net expense (credit)	$ 66	$ (233)	$ 132	$ (464)