Organization and summary of significant accounting policies - Cash and Equivalents (Details) - USD ($) $ in Millions	Feb. 01, 2020	Feb. 02, 2019
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 374.5	$ 195.4
Cash and cash equivalents held in money markets and other accounts
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	326.2	164.5
Cash equivalents from third-party credit card issuers
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	46.3	29.1
Cash on hand
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 2.0	$ 1.8

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3044-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118951113&loc=d3e6676-107765

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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