Accounts receivable, net - Credit Quality of Finance Receivables (Details) - USD ($) $ in Millions	Jan. 30, 2021	Aug. 01, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Total at amortized cost	$ 97.5	$ 24.3
Near Prime
Financing Receivable, Credit Quality Indicator [Line Items]
Total at amortized cost	46.6	10.9
Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Total at amortized cost	38.9	10.7
Deep Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
Total at amortized cost	$ 12.0	$ 2.7