Debt (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	May 02, 2015	Jan. 31, 2015
Line of Credit Facility [Line Items]
Number of unsecured credit facilities	2	2
Available borrowings under credit facilities	$ 80.0	$ 80.0
August 2014 Facility [Member]
Line of Credit Facility [Line Items]
Expiration date of renewed facility	Aug. 21, 2015	Aug. 21, 2015
Maximum borrowing capacity under renewed facility	30.0	30.0
Description of variable interest rate basis	Higher of prime, federal funds plus 0.5% or LIBOR	Higher of prime, federal funds plus 0.5% or LIBOR
Basis spread on variable interest rate (in hundredths)	0.50%	0.50%
Debt outstanding at period end	0	0
November 2014 Facility [Member]
Line of Credit Facility [Line Items]
Expiration date of renewed facility	Nov. 18, 2015	Nov. 18, 2015
Maximum borrowing capacity under renewed facility	50.0	50.0
Description of variable interest rate basis	prime	prime
Basis spread on variable interest rate (in hundredths)	2.00%	2.00%
Debt outstanding at period end	$ 0	$ 0