XML 107 R130.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Employee Benefits - Sensitivity of Disclosures to Changes in Selected Assumptions (Detail) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2019 USD ($)
Postretirement Benefit Plan [Member] |
Defined Benefit Plan Disclosure [Line Items] |
25 BP Decrease in Discount Rate, Change in ABO | $ 1,944
25 BP Decrease in Discount Rate, Change in pension expense | 40
U.S. Pension Plans [Member] | Pension Plan [Member] |
Defined Benefit Plan Disclosure [Line Items] |
25 BP Decrease in Discount Rate, Change in PBO | 14,613
25 BP Decrease in Discount Rate, Change in ABO | 14,534
25 BP Decrease in Discount Rate, Change in pension expense | (102)
25 BP Decrease in Long-Term Rate of Return, Change in pension expense | 1,248
Non-U.S. Plans [Member] | Pension Plan [Member] |
Defined Benefit Plan Disclosure [Line Items] |
25 BP Decrease in Discount Rate, Change in PBO | 55,415
25 BP Decrease in Discount Rate, Change in ABO | 55,374
25 BP Decrease in Discount Rate, Change in pension expense | 2,687
25 BP Decrease in Long-Term Rate of Return, Change in pension expense | $ 1,935

X
- Definition Defined benefit plan, effect of twenty five base point decrease in discount rate in accumulated benefit obligation + References No definition available. + Details
Name: | iff_DefinedBenefitPlanEffectOfTwentyFiveBasePointDecreaseInDiscountRateInAccumulatedBenefitObligation
Namespace Prefix: | iff_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Defined benefit plan, effect of twenty five base point decrease in discount rate in pension expense + References No definition available. + Details
Name: | iff_DefinedBenefitPlanEffectOfTwentyFiveBasePointDecreaseInDiscountRateInPensionExpense
Namespace Prefix: | iff_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Defined benefit plan, effect of twenty five base point decrease in discount rate in projected benefit obligation + References No definition available. + Details
Name: | iff_DefinedBenefitPlanEffectOfTwentyFiveBasePointDecreaseInDiscountRateInProjectedBenefitObligation
Namespace Prefix: | iff_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Defined benefit plan, effect of twenty five base point decrease in long term rate of return in pension expense + References No definition available. + Details
Name: | iff_DefinedBenefitPlanEffectOfTwentyFiveBasePointDecreaseInLongTermRateOfReturnInPensionExpense
Namespace Prefix: | iff_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanSponsorLocationAxis=country_US
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanSponsorLocationAxis=us-gaap_ForeignPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |