Restructuring And Related Cost, Expected Number Of Sites Closed

No definition available.

Name:	iff_RestructuringAndRelatedCostExpectedNumberOfSitesClosed
Namespace Prefix:	iff_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Restructuring And Related Cost, Number Of Sites Closed

+ References

No definition available.

+ Details

Name:	iff_RestructuringAndRelatedCostNumberOfSitesClosed
Namespace Prefix:	iff_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of other expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses associated with a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.P.3)
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140864-122747

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

+ Details

Name:	us-gaap_OtherRestructuringCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The expected number of positions to be eliminated as a result of restructuring activities.

+ References

No definition available.

+ Details

Name:	us-gaap_RestructuringAndRelatedCostExpectedNumberOfPositionsEliminated
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.P.3)
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140864-122747

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

+ Details

Name:	us-gaap_RestructuringCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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_RestructuringCostAndReserveLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RestructuringPlanAxis=iff_FrutaromIntegrationInitiativeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=iff_A2017ProductivityProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_EmployeeSeveranceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=iff_A2019SeveranceInitiativesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=srt_AsiaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=us-gaap_EMEAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=srt_LatinAmericaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=srt_NorthAmericaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Restructuring and Other Charges, Net - Additional Information (Detail) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2020 USD ($)	Mar. 31, 2020 Facility	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) Facility	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) Facility Position	Dec. 31, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 1,884		$ 2,525	$ 6,802	$ 18,699
Frutarom Integration Initiative
Restructuring Cost and Reserve [Line Items]
Expected number of sites closed \| Facility				35
Number of facilities closed \| Facility				5		10
2017 Productivity Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges							$ 24,500
Employee Severance \| Frutarom Integration Initiative
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				$ 17,200
Employee Severance \| Frutarom Integration Initiative \| Minimum
Restructuring Cost and Reserve [Line Items]
Payments for restructuring				40,000
Employee Severance \| Frutarom Integration Initiative \| Maximum
Restructuring Cost and Reserve [Line Items]
Payments for restructuring				$ 50,000
Employee Severance \| 2019 Severance Initiatives
Restructuring Cost and Reserve [Line Items]
Restructuring Charges						$ 21,300
Number of positions expected to be eliminated \| Position						190
Payments for restructuring						$ 25,000
Employee Severance \| 2017 Productivity Program
Restructuring Cost and Reserve [Line Items]
Payments for restructuring							$ 25,000
Greater Asia \| Frutarom Integration Initiative
Restructuring Cost and Reserve [Line Items]
Number of facilities closed \| Facility		1
Europe, Africa and Middle East \| Frutarom Integration Initiative
Restructuring Cost and Reserve [Line Items]
Number of facilities closed \| Facility				2		6
Latin America \| Frutarom Integration Initiative
Restructuring Cost and Reserve [Line Items]
Number of facilities closed \| Facility				1		2
North America \| Frutarom Integration Initiative
Restructuring Cost and Reserve [Line Items]
Number of facilities closed \| Facility				2		1