Document And Entity Information - USD ($)	12 Months Ended
	Dec. 30, 2018	Feb. 18, 2019	Jun. 29, 2018
Document Information [Line Items]
Entity Registrant Name	INTERFACE INC
Entity Central Index Key	0000715787
Trading Symbol	tile
Current Fiscal Year End Date	--12-30
Entity Filer Category	Large Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding (in shares)		59,453,784
Entity Public Float			$ 1,343,752,725
Document Type	10-K
Document Period End Date	Dec. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Shell Company	false