Investments (Assets Measured at Fair Value on a Recurring Basis) (Details) (USD $) In Thousands	Apr. 30, 2011	Jan. 29, 2011	May 01, 2010
Total assets measured at fair value	$ 15,466	$ 17,286	$ 17,798
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Total assets measured at fair value	6,669	8,031	5,096
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Auction-Rate Securities [Member]
Total assets measured at fair value
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate Securities [Member]
Total assets measured at fair value
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Government and Agency Securities [Member]
Total assets measured at fair value	6,669	8,031	5,096
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage-Backed Securities [Member]
Total assets measured at fair value
Significant Other Observable Inputs (Level 2) [Member]
Total assets measured at fair value	8,797	9,255	11,802
Significant Other Observable Inputs (Level 2) [Member] | Auction-Rate Securities [Member]
Total assets measured at fair value
Significant Other Observable Inputs (Level 2) [Member] | Corporate Securities [Member]
Total assets measured at fair value	7,745	8,062	9,881
Significant Other Observable Inputs (Level 2) [Member] | U.S. Government and Agency Securities [Member]
Total assets measured at fair value
Significant Other Observable Inputs (Level 2) [Member] | Mortgage-Backed Securities [Member]
Total assets measured at fair value	1,052	1,193	1,921
Auction-Rate Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Total assets measured at fair value			900
Corporate Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Total assets measured at fair value
U.S. Government and Agency Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Total assets measured at fair value
Mortgage-Backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Total assets measured at fair value
Significant Unobservable Inputs (Level 3) [Member]
Total assets measured at fair value			900
Auction-Rate Securities [Member]
Total assets measured at fair value			900
Corporate Securities [Member]
Total assets measured at fair value	7,745	8,062	9,881
U.S. Government and Agency Securities [Member]
Total assets measured at fair value	6,669	8,031	5,096
Mortgage-Backed Securities [Member]
Total assets measured at fair value	$ 1,052	$ 1,193	$ 1,921