XML 51 R40.htm IDEA: XBRL DOCUMENT
v3.19.2

Note 6 - Derivative Instruments (Details Textual) - USD ($) $ in Millions | Jun. 30, 2019 | Mar. 31, 2019 | Oct. 01, 2017
--- | --- | --- | ---
Interest Rate Swap 1 [Member] |  |  |
Derivative, Notional Amount |  |  | $ 100
Interest Rate Swap 2 [Member] |  |  |
Derivative, Notional Amount |  | $ 150 |
Interest Rate Swap [Member] |  |  |
Derivative, Notional Amount | $ 250 |  |
Foreign Exchange Forward [Member] |  |  |
Derivative, Notional Amount | $ 12 |  |

X
- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
Name: | invest_DerivativeNotionalAmount
Namespace Prefix: | invest_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=tile_InterestRateSwap1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=tile_InterestRateSwap2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeForwardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |