Fair value measurement - Outstanding Debt (Details) - Senior Notes - Level 2 - USD ($) $ in Millions	Jul. 29, 2023	Jan. 28, 2023	Jul. 30, 2022
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Outstanding debt	$ 147.5	$ 147.4	$ 147.2
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Outstanding debt	$ 145.1	$ 144.9	$ 146.2

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
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Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
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-Publisher FASB
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Name:	us-gaap_DebtInstrumentFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant