Accounts receivable - Additional Information (Details) - CarVal and Castlelake	1 Months Ended	12 Months Ended
	Jun. 30, 2018	Jan. 30, 2021	Feb. 01, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, purchase of forward flow receivables, term	5 years
Accounts receivable, sale, percentage of revenue			7.00%
Accounts receivable, remaining purchase price of receivables sold, percentage	5.00%
Scenario, Forecast
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, sale, percentage of revenue		2.50%