Shareholders' Equity - Narrative (Details) - USD ($)	3 Months Ended
Apr. 05, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	20,000
Options, exercise price range (dollars per share)	$ 12.43
Stock options granted in period (in shares)	0	0
Stock options exercised in period (in shares)	7,500	10,000
Stock options forfeited in period (in shares)	0	5,000
Share-based Payment Arrangement, Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	$ 0	$ 0
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	$ (700,000)	$ 800,000
Stock options granted (in shares)	199,600	224,000
Unrecognized compensation costs related to unvested restricted stock	$ 5,200,000
Restricted Stock \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period	1 year
Restricted Stock \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period	3 years
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	$ (2,200,000)	$ 2,000,000.0
Stock options granted (in shares)	263,600
Number of shares that may be issued in settlement of the performance shares to the award recipient, upper limit (percentage)	200.00%
Unrecognized compensation expense	$ 7,400,000
Performance Shares \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period	1 year
Performance Shares \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period	3 years
Restricted Stock and Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense, tax benefit	$ 1,000,000.0
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
tile_ForfeituresAndCompensationExpenseRelatedToStockAwardsValue	25,000	$ 22,000
ForfeitureOfShareBasedCompensation [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	1,400,000
tile_ForfeituresAndCompensationExpenseRelatedToStockAwardsValue	100,000
ForfeitureOfShareBasedCompensation [Member] \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	600,000
ForfeitureOfShareBasedCompensation [Member] \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 800,000

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The maximum percentage of the shares issued compared to the unit amount of the equity instruments, other than options, that are exercised to acquire the shares issued.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Represents the quantification of the effect of adopting the new accounting standard or change in accounting principle expected by the entity to have a significant effect on the entity's financial statements.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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Number of share options (or share units) exercised during the current period.

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