Interim Financial Results (Unaudited) (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				12 Months Ended			3 Months Ended
	Oct. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Jul. 31, 2012	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2014 Store Assets	Jul. 31, 2013 Store Assets	Jan. 31, 2013 Store Assets	Oct. 31, 2012 Store Assets
Property Plant And Equipment [Line Items]
Impairment charges related to store asset					$ 0.3	$ 1.4	$ 0.8	$ 0.2	$ 0.1	$ 1.3	$ 0.1
Abandoned lease expense recognized	$ 0.2	$ 0.1	$ 0.2	$ 0.1