Derivatives and hedging activities (Details) (USD $)	3 Months Ended		6 Months Ended					1 Months Ended	3 Months Ended	6 Months Ended
	Aug. 03, 2012 swap	Jul. 29, 2011	Aug. 03, 2012 swap	Jul. 29, 2011	Aug. 03, 2012 Accrued expenses and other current liabilities	Feb. 03, 2012 Accrued expenses and other current liabilities	Aug. 03, 2012 Non-current Other Liabilities	Jun. 01, 2012 Interest rate swaps May 2012	Aug. 03, 2012 Interest rate swaps May 2012	Aug. 03, 2012 Interest rate swaps May 2012	May 31, 2012 Interest rate swaps May 2012
Derivatives and hedging activities
Interest rate swaps combined notional value	$ 1,175,000,000		$ 1,175,000,000
Number of interest rate swap agreements	4		4
Estimated amount to be reclassified during the next 52 weeks period	6,200,000		6,200,000
Derivatives designated as hedging instruments
Derivative financial instruments					3,117,000	10,820,000	5,376,000
Notional amount											875,000,000
Variable rate basis								LIBOR	LIBOR	LIBOR
Fixed rate of interest on interest rate swaps (as a percent)									3.34%	3.34%	3.34%
Pre-tax effect of derivative instruments on the condensed consolidated statements of comprehensive income
Loss related to effective portion of derivative recognized in OCI	8,506,000	1,235,000	8,542,000	2,838,000
Loss related to effective portion of derivative reclassified from Accumulated OCI to Interest expense	4,386,000	8,821,000	8,571,000	18,141,000
(Gain) loss related to ineffective portion of derivative recognized in Other (income) expense	(2,434,000)	103,000	(2,392,000)	208,000
Credit-risk-related contingent features
Fair value of interest rate swaps in a net liability position	8,800,000		8,800,000
Collateral or assets required to settle interest rate swap obligations, estimated termination value	$ 8,800,000		$ 8,800,000