Fair Value Measurement - Amortized Cost and Fair Market Value of Securities by Contractual Maturity (Details) - USD ($)
$ in Thousands
Oct. 29, 2016
Jan. 30, 2016
Amortized Cost    
Mature in one year or less $ 34,132 $ 32,671
Mature after one year through five years 29,183 30,890
Total 63,315 63,561
Fair Market Value    
Mature in one year or less 34,135 32,675
Mature after one year through five years 29,213 30,916
Total Fair Market Value 63,348 $ 63,591
Changes among the fair value levels    
Changes between Level 1 to Level 2, Assets $ 0