Organization And Basis Of Presentation (Details) (USD $)	6 Months Ended
	Jul. 31, 2011	Aug. 01, 2010
Net cash used in investment activities in the respective prior period, after the reclassification	$ (49,080,000)	$ (43,918,000)
Reclassification [Member]
The amount of a reclassification between Cash and Cash Equivalent and Temporary Investment made to prior period financial statement		28,000,000
Number of weeks for the fourth quarter for a 53-week fiscal year		14
Cash used to purchase available-for-sale investments in the respective prior period before the reclassification		54,000,000
Cash used to purchase available-for-sale investments in the respective prior period after the reclassification		82,000,000
Net cash used in investment activities in the respective prior period, before the reclassification		$ 16,000,000
Reclassification [Member] | 52 Week Fiscal Year [Member]
Number of weeks in a fiscal year		52
Number of weeks in a quarter for 52 weeks fiscal period		13
Reclassification [Member] | 53 Week Fiscal Year [Member]
Number of weeks in a fiscal year		53
Number of weeks for the fourth quarter for a 53-week fiscal year		14
Reclassification [Member] | Time Deposits Range One [Member]
Original maturity period (in months) of time deposits classified as Temporary Investments		six
Reclassification [Member] | Time Deposits Range Two [Member]
Original maturity period (in months) of time deposits classified as Temporary Investments		nine
Reclassification [Member] | Time Deposits Range Three [Member]
Original maturity period (in months) of time deposits classified as Temporary Investments		twelve
52 Week Fiscal Year [Member]
Number of weeks in a fiscal year	52
53 Week Fiscal Year [Member]
Number of weeks in a fiscal year	53
Time Deposits Range One [Member]
Original maturity period (in months) of time deposits classified as Temporary Investments	six
Time Deposits Range Two [Member]
Original maturity period (in months) of time deposits classified as Temporary Investments	nine
Time Deposits Range Three [Member]
Original maturity period (in months) of time deposits classified as Temporary Investments	twelve