Stock-based compensation - Market based restricted stock units (Details) shares in Thousands	12 Months Ended
Feb. 01, 2020 shares
Market-based restricted stock units \| Chief Executive Officer
Stock-based compensation
Granted (in shares)	28

Net number of share options (or share units) granted during the period.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(01)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration