Note 3 - Earnings Per Share (Details) - Distributed and Undistributed Earnings (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jul. 01, 2012	Jun. 30, 2013	Jul. 01, 2012
Basic Earnings Per Share Attributable to Common Stockholders:
Basic earnings per share attributable to common stockholders	$ 0.17	$ 0.16	$ 0.27	$ 0.07
Diluted Earnings Per Share Attributable to Common Stockholders:
Diluted earnings per share attributable to common stockholders	$ 0.17	$ 0.16	$ 0.27	$ 0.07
Basic earnings (loss) per share attributable to Interface, Inc. common shareholders
Basic earnings per share attributable to Interface, Inc. common shareholders	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Diluted earnings (loss) per share attributable to Interface, Inc. common shareholders
Diluted earnings per share attributable to Interface, Inc. common shareholders	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Basic earnings per share attributable to Interface, Inc. common shareholders	$ 0.17	$ 0.16	$ 0.27	$ 0.07
Diluted earnings per share attributable to Interface, Inc. common shareholders	$ 0.17	$ 0.16	$ 0.27	$ 0.07
Distributed Earnings [Member]
Basic Earnings Per Share Attributable to Common Stockholders:
Basic earnings per share attributable to common stockholders	$ 0.03	$ 0.02	$ 0.05	$ 0.04
Diluted Earnings Per Share Attributable to Common Stockholders:
Diluted earnings per share attributable to common stockholders	$ 0.03	$ 0.02	$ 0.05	$ 0.04
Basic earnings (loss) per share attributable to Interface, Inc. common shareholders
Basic earnings per share attributable to Interface, Inc. common shareholders	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Diluted earnings (loss) per share attributable to Interface, Inc. common shareholders
Diluted earnings per share attributable to Interface, Inc. common shareholders	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Undistributed Earnings [Member]
Basic Earnings Per Share Attributable to Common Stockholders:
Basic earnings per share attributable to common stockholders	$ 0.14	$ 0.14	$ 0.22	$ 0.03
Diluted Earnings Per Share Attributable to Common Stockholders:
Diluted earnings per share attributable to common stockholders	$ 0.14	$ 0.14	$ 0.22	$ 0.03
Basic earnings (loss) per share attributable to Interface, Inc. common shareholders
Basic earnings per share attributable to Interface, Inc. common shareholders	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Diluted earnings (loss) per share attributable to Interface, Inc. common shareholders
Diluted earnings per share attributable to Interface, Inc. common shareholders	$ 0.00	$ 0.00	$ 0.00	$ 0.00

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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