Note 4 - Fair Value of Financial Instruments (Details) $ in Millions	Jan. 03, 2016 USD ($)
Fair Value Disclosures [Abstract]
Company-owned Life Insurance Assets, Fair Value Disclosure	$ 24.8

The fair value disclosure of company-owned life insurance assets.

No definition available.

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