Note 7 - Property and Equipment (Details Textual) $ in Millions	Dec. 30, 2018 USD ($)
Estimated Cost To Complete Approved Projects And Current Construction In Progress	$ 92.2

Estimated Cost To Complete Approved Projects And Current Construction In Progress

No definition available.

Name:	tile_EstimatedCostToCompleteApprovedProjectsAndCurrentConstructionInProgress
Namespace Prefix:	tile_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant