Basis of Presentation (Details) supplier in Thousands, product in Millions	9 Months Ended
Sep. 30, 2017 product supplier
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of products offered (more than) \| product	8
Number of suppliers providing products offered (more than) \| supplier	10

The minimum number of suppliers providing products offered by the entity.

No definition available.

Name:	w_MinimumNumberOfSuppliers
Namespace Prefix:	w_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration