Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 18, 2018	Jun. 30, 2017
Document Information [Line Items]
Entity Registrant Name	INTERFACE INC
Entity Central Index Key	0000715787
Trading Symbol	tile
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Entity Common Stock, Shares Outstanding (in shares)		59,337,559
Entity Public Float			$ 1,215,708,813
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Amendment Flag	false