Revolving Line of Credit (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	9 Months Ended
	Oct. 31, 2011 Revolving credit facility	Nov. 02, 2013 Revolving credit facility item	Nov. 02, 2013 Revolving credit facility LIBOR Rate Loans	Nov. 02, 2013 Revolving credit facility LIBOR Base Rate Loans	Nov. 02, 2013 Revolving credit facility Bank of America's prime rate Base Rate Loans	Nov. 02, 2013 Revolving credit facility Federal Funds Rate Base Rate Loans	Nov. 02, 2013 Prior credit facility	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%
Amount of outstanding borrowings prior to cash dividend payment within specified period, per covenant		0
Period prior to cash dividend payment when no borrowings may be outstanding, per covenant		30 days
Amount of expected borrowings subsequent to cash dividend payment within specified period, per covenant		0
Period subsequent to cash dividend payment when no borrowings may be expected, per covenant		30 days
Borrowings outstanding		$ 0					$ 0