Note 2 - Revenue Recognition - Disaggregation of Revenue (Details)	3 Months Ended
Apr. 01, 2018
Americas [Member]
Americas	56.20%
Europe [Member]
Americas	27.70%
Asia Pacific [Member]
Americas	16.10%

The percent of revenue due to direct sales to customers.

No definition available.

Name:	tile_PercentOfRevenueDueToSalesToCustomers
Namespace Prefix:	tile_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration