Organization And Basis Of Presentation (Reclassification) (Details) (USD $)	9 Months Ended
	Oct. 30, 2011	Oct. 31, 2010
Organization And Basis Of Presentation [Line Items]
Net cash used in investment activities in the respective prior period, after the reclassification	$ (16,198,000)	$ (81,781,000)
Reclassification [Member]
Organization And Basis Of Presentation [Line Items]
The amount of a reclassification between cash and cash equivalent and temporary investment made to prior period financial statement		59,000,000
Investment maturities during the interim period		5,000,000
Cash used to purchase available-for-sale investments in the respective prior period before the reclassification		85,000,000
Cash used to purchase available-for-sale investments in the respective prior period after the reclassification		149,000,000
Net cash used in investment activities in the respective prior period, before the reclassification		23,000,000
Net cash used in investment activities in the respective prior period, after the reclassification		$ 82,000,000
Reclassification [Member] | Time Deposits Range One [Member]
Organization And Basis Of Presentation [Line Items]
Original maturity period (in months) of time deposits classified as Temporary Investments	six	six
Reclassification [Member] | Time Deposits Range Two [Member]
Organization And Basis Of Presentation [Line Items]
Original maturity period (in months) of time deposits classified as Temporary Investments	nine	nine
Reclassification [Member] | Time Deposits Range Three [Member]
Organization And Basis Of Presentation [Line Items]
Original maturity period (in months) of time deposits classified as Temporary Investments	twelve	twelve