Summary of significant accounting policies - Share-Based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
Feb. 01, 2020	Feb. 02, 2019	Feb. 03, 2018
Summary of significant accounting policies
Stock compensation expense	$ 25,642	$ 27,489	$ 24,399

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=118932676&loc=d3e3602-108585

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