Derivatives and hedging activities (Details) (USD $)	3 Months Ended		9 Months Ended
	Oct. 28, 2011 InterestRateSwapAgreements	Oct. 29, 2010	Oct. 28, 2011 InterestRateSwapAgreements	Oct. 29, 2010	Oct. 28, 2011 Accrued expenses and other current liabilities	Oct. 28, 2011 Non-current Other Liabilities	Jan. 28, 2011 Non-current Other Liabilities
Derivatives and hedging activities
Number of interest rate swap agreements	3		3
Interest rate swaps combined notional value	$ 686,700,000		$ 686,700,000
Estimated amount to be reclassified during the next 52 weeks period	11,500,000		11,500,000
Derivatives designated as hedging instruments
Derivative financial instruments					7,842,000	7,273,000	34,923,000
Effect of derivative instruments on condensed consolidated statement of income
Loss related to effective portion of derivative recognized in OCI	482,000	5,104,000	3,319,000	20,540,000
Loss related to effective portion of derivative reclassified from Accumulated OCI to Interest expense	5,570,000	9,790,000	23,710,000	33,192,000
Loss related to ineffective portion of derivative recognized in Other (income) expense	52,000	123,000	261,000	408,000
Credit-risk-related contingent features
Fair value of interest rate swaps in a net liability position	19,400,000		19,400,000
Collateral or assets required to settle interest rate swap obligations, estimated termination value	$ 19,400,000		$ 19,400,000