Property and equipment - Capitalized Interest (Details) - USD ($)	12 Months Ended
Feb. 03, 2018	Jan. 28, 2017
Property and equipment
Capitalized interest	$ 0	$ 0

Amount of interest costs capitalized disclosed as an adjusting item to interest costs incurred.

No definition available.

Name:	us-gaap_InterestCostsCapitalizedAdjustment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration