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Note 13 - Taxes on Income (Details) (USD $) | 12 Months Ended |
--- | --- | ---
Dec. 28, 2014 | Dec. 29, 2013 | Dec. 30, 2012 | Jan. 01, 2012
Note 13 - Taxes on Income (Details) [Line Items] |  |  |  |
Deferred Tax Assets, Operating Loss Carryforwards, Foreign | $ 4,000,000 us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsForeign |  |  |
Operating Loss Carryforwards, Valuation Allowance | 10,298,000 us-gaap_OperatingLossCarryforwardsValuationAllowance | 9,577,000 us-gaap_OperatingLossCarryforwardsValuationAllowance |  |
Unrecognized Tax Benefits, Period Increase (Decrease) | (21,800,000)us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease | (21,800,000)us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease |  |
Effective Income Tax Rate Reconciliation, Percent | 30.60%us-gaap_EffectiveIncomeTaxRateContinuingOperations | 30.10%us-gaap_EffectiveIncomeTaxRateContinuingOperations | 39.90%us-gaap_EffectiveIncomeTaxRateContinuingOperations |
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent | 35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate |  |  |
Undistributed Earnings of Foreign Subsidiaries | 261,000,000 us-gaap_UndistributedEarningsOfForeignSubsidiaries |  |  |
Deferred Tax Liabilities, Undistributed Foreign Earnings | 5,600,000 us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings |  |  |
Foreign Earnings to be Repatriated | 2,400,000 tile_ForeignEarningsToBeRepatriated |  |  |
Unrecognized Tax Benefits | 27,301,000 us-gaap_UnrecognizedTaxBenefits | 27,361,000 us-gaap_UnrecognizedTaxBenefits | 25,186,000 us-gaap_UnrecognizedTaxBenefits | 7,736,000 us-gaap_UnrecognizedTaxBenefits
Unrecognized Tax Benefits that Would Impact Effective Tax Rate | 27,300,000 us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate |  |  |
Unrecognized Tax Benefits That Would Require To Settle Through Cash | 5,500,000 tile_UnrecognizedTaxBenefitsThatWouldRequireToSettleThroughCash |  |  |
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued | (1,200,000)us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued |  |  |
Income Tax Expense (Benefit) | 10,934,000 us-gaap_IncomeTaxExpenseBenefit | 20,749,000 us-gaap_IncomeTaxExpenseBenefit | 15,204,000 us-gaap_IncomeTaxExpenseBenefit |
Earliest Tax Year [Member] | Domestic Tax Authority [Member] |  |  |  |
Note 13 - Taxes on Income (Details) [Line Items] |  |  |  |
Open Tax Year | 2003 |  |  |
Earliest Tax Year [Member] | State and Local Jurisdiction [Member] |  |  |  |
Note 13 - Taxes on Income (Details) [Line Items] |  |  |  |
Open Tax Year | 2009 |  |  |
Earliest Tax Year [Member] | Foreign Tax Authority [Member] |  |  |  |
Note 13 - Taxes on Income (Details) [Line Items] |  |  |  |
Open Tax Year | 2004 |  |  |
Deferred Compensation, Share-based Payments [Member] | Domestic Tax Authority [Member] |  |  |  |
Note 13 - Taxes on Income (Details) [Line Items] |  |  |  |
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration | 28,900,000 us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration / us-gaap_IncomeTaxAuthorityAxis = us-gaap_DomesticCountryMember / us-gaap_StatementEquityComponentsAxis = us-gaap_DeferredCompensationShareBasedPaymentsMember |  |  |
Domestic Tax Authority [Member] |  |  |  |
Note 13 - Taxes on Income (Details) [Line Items] |  |  |  |
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration | 129,000,000 us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration / us-gaap_IncomeTaxAuthorityAxis = us-gaap_DomesticCountryMember |  |  |
Deferred Tax Liability Not Recognized, Amount of Unrecognized Deferred Tax Liability, Undistributed Earnings of Foreign Subsidiaries | 800,000 us-gaap_DeferredTaxLiabilityNotRecognizedAmountOfUnrecognizedDeferredTaxLiabilityUndistributedEarningsOfForeignSubsidiaries / us-gaap_IncomeTaxAuthorityAxis = us-gaap_DomesticCountryMember |  |  |
State and Local Jurisdiction [Member] | Continuing Operations [Member] |  |  |  |
Note 13 - Taxes on Income (Details) [Line Items] |  |  |  |
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration | 209,000,000 us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration / us-gaap_IncomeTaxAuthorityAxis = us-gaap_StateAndLocalJurisdictionMember / us-gaap_StatementOperatingActivitiesSegmentAxis = us-gaap_SegmentContinuingOperationsMember |  |  |
State and Local Jurisdiction [Member] |  |  |  |
Note 13 - Taxes on Income (Details) [Line Items] |  |  |  |
Operating Loss Carryforwards, Valuation Allowance | 163,700,000 us-gaap_OperatingLossCarryforwardsValuationAllowance / us-gaap_IncomeTaxAuthorityAxis = us-gaap_StateAndLocalJurisdictionMember |  |  |
Foreign Tax Authority [Member] |  |  |  |
Note 13 - Taxes on Income (Details) [Line Items] |  |  |  |
Deferred Tax Liability Not Recognized, Amount of Unrecognized Deferred Tax Liability, Undistributed Earnings of Foreign Subsidiaries | 100,000 us-gaap_DeferredTaxLiabilityNotRecognizedAmountOfUnrecognizedDeferredTaxLiabilityUndistributedEarningsOfForeignSubsidiaries / us-gaap_IncomeTaxAuthorityAxis = us-gaap_ForeignCountryMember |  |  |
BAPA Program [Member] |  |  |  |
Note 13 - Taxes on Income (Details) [Line Items] |  |  |  |
Income Tax Expense (Benefit) |  | (1,900,000)us-gaap_IncomeTaxExpenseBenefit / us-gaap_IncomeTaxAuthorityAxis = tile_BAPAProgramMember |  |
Canadian Subsidiary [Member] |  |  |  |
Note 13 - Taxes on Income (Details) [Line Items] |  |  |  |
Increase (Decrease) in Income Taxes Payable |  | (600,000)us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable / us-gaap_SubsegmentsAxis = tile_CanadianSubsidiaryMember |  |
Continuing Operations [Member] |  |  |  |
Note 13 - Taxes on Income (Details) [Line Items] |  |  |  |
Income Tax Expense (Benefit) | 10,934,000 us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementOperatingActivitiesSegmentAxis = us-gaap_SegmentContinuingOperationsMember | 20,749,000 us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementOperatingActivitiesSegmentAxis = us-gaap_SegmentContinuingOperationsMember | 15,204,000 us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementOperatingActivitiesSegmentAxis = us-gaap_SegmentContinuingOperationsMember |
Discontinued Operations [Member] |  |  |  |
Note 13 - Taxes on Income (Details) [Line Items] |  |  |  |
Deferred Tax Assets, Operating Loss Carryforwards, State and Local | 166,000,000 us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal / us-gaap_StatementOperatingActivitiesSegmentAxis = us-gaap_SegmentDiscontinuedOperationsMember |  |  |
Income Tax Expense (Benefit) | $ 0 us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementOperatingActivitiesSegmentAxis = us-gaap_SegmentDiscontinuedOperationsMember | $ 0 us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementOperatingActivitiesSegmentAxis = us-gaap_SegmentDiscontinuedOperationsMember | $ (9,164,000)us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementOperatingActivitiesSegmentAxis = us-gaap_SegmentDiscontinuedOperationsMember |

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