Summary of significant accounting policies - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
Jan. 30, 2021	Feb. 01, 2020	Feb. 02, 2019
Summary of significant accounting policies
Stock-base compensation	$ 27,583	$ 25,642	$ 27,489

Amount of noncash expense for share-based payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration