Derivatives and hedging activities (Details 2) (USD $)	3 Months Ended		6 Months Ended
	Aug. 02, 2013	Aug. 03, 2012	Aug. 02, 2013	Aug. 03, 2012	Aug. 02, 2013 Derivatives not designated as hedges item	Aug. 03, 2012 Derivatives not designated as hedges item	Aug. 02, 2013 Noncurrent Other liabilities	Feb. 01, 2013 Noncurrent Other liabilities
Derivatives designated as hedging instruments
Derivative financial instruments							$ 4,411,000	$ 4,822,000
Derivative instruments held
Number of derivative instruments which are non-designated hedges					0	0
Pre-tax effect of derivative instruments on the condensed consolidated statements of comprehensive income
(Gain) loss related to effective portion of derivatives recognized in OCI	(809,000)	8,506,000	14,518,000	8,542,000
Loss related to effective portion of derivatives reclassified from Accumulated OCI to Interest expense	1,193,000	4,386,000	2,124,000	8,571,000
Gain related to ineffective portion of derivatives recognized in Other (income) expense		(2,434,000)		(2,392,000)
Credit-risk-related contingent features
Fair value of interest rate swaps in a net liability position	4,500,000		4,500,000
Collateral or assets required to settle interest rate swap obligations, estimated termination value	$ 4,500,000		$ 4,500,000