Summary of significant accounting policies - Advertising (Details) - USD ($) $ in Thousands	12 Months Ended
Jan. 30, 2021	Feb. 01, 2020	Feb. 02, 2019
Summary of significant accounting policies
Advertising expense	$ 281,573	$ 317,865	$ 294,489
Advertising expense as a percentage of net sales	4.60%	4.30%	4.40%
Prepaid advertising costs	$ 7,112	$ 9,605

Amount of consideration paid in advance for advertising that provides economic benefits within a future period of one year or the normal operating cycle, if longer.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant