Accounts receivable, net - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jul. 28, 2012 Day	Jul. 28, 2012 UK	Jan. 28, 2012 UK	Jul. 30, 2011 UK
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage allowance on losses	100.00%
Losses allowance maturity date, (in days)	90
Finance receivable age, (in days)	90
Gross accounts receivable		$ 8.7	$ 11.3	$ 6.2
Valuation of allowance		$ 0.7	$ 0.5	$ 0.6