Revolving Line of Credit (Details) (USD $)
In Millions, unless otherwise specified
1 Months Ended 6 Months Ended
Oct. 31, 2011
Revolving credit facility
Jul. 28, 2012
Revolving credit facility
item
Jul. 28, 2012
Revolving credit facility
LIBOR Rate Loans
Jul. 28, 2012
Revolving credit facility
LIBOR
Base Rate Loans
Jul. 28, 2012
Revolving credit facility
Bank of America's prime rate
Base Rate Loans
Jul. 28, 2012
Revolving credit facility
Federal Funds Rate
Base Rate Loans
Oct. 27, 2011
Prior credit facility
Revolving Line of Credit              
Term of credit facility 5 years            
Maximum borrowing capacity   $ 50         $ 20
Borrowing capacity, accordion feature   25          
Maximum borrowing capacity including accordion expansion   $ 75          
Variable interest rate basis     LIBOR LIBOR prime rate Federal Funds Rate  
Margin added to variable rate (as a percent)     1.50% 1.50% 0.50% 1.00%  
Number of covenants   1          
Unused commitment fee (as a percent)   0.25%          
Period prior to cash dividend payment when no borrowings may be outstanding, per covenant   30 days          
Period subsequent to cash dividend payment when no borrowings may be expected, per covenant   30 days