Summary of Significant Accounting Policies Schedule of Fair Value Information (Tables)
 12 Months Ended
Jan. 28, 2012
Summary of Significant Accounting Policies [Abstract]  
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
 
January 28, 2012
 
Level 1
Level 2
Level 3
 
(in thousands)
U.S. treasury securities funds
$
131,543

$
—

$
—

 
 
 
January 29, 2011
 
Level 1
Level 2
Level 3
 
(in thousands)
U.S. treasury securities funds
$
168,929

$
—

$
—