Employee Benefits - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015
Non-Qualified U.S. Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to the plans	$ 1.1
Non-U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to the plans	19.1
Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to the plan	5
Contribution to other postretirement plans	1.7
Maximum [Member] \| Non-Qualified U.S. Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to the plan	35.0
Maximum [Member] \| Non-U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to the plan	$ 30.0

Defined benefit plan expected contribution by employer

No definition available.

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Namespace Prefix:	iff_
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Balance Type:	debit
Period Type:	duration

- Definition

The increase in the fair value of plan assets from contributions made by the employer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)(3)

-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

+ Details

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- Details

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- Definition

Amount of employer's best estimate of contributions expected to be paid to the plan in the current remaining fiscal period.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

The amount of cash or cash equivalents contributed during the reporting period by the entity to fund non-pension postretirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 25

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3536-108585

+ Details

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- Details

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