CONSOLIDATED STATEMENT OF INCOME AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Net sales	$ 3,977,539	$ 3,398,719	$ 3,116,350
Cost of goods sold	2,294,832	1,926,256	1,720,787
Gross Profit	1,682,707	1,472,463	1,395,563
Research and development expenses	311,583	295,469	258,863
Selling and administrative expenses	707,461	570,144	572,518
Restructuring and other charges, net	5,079	19,711	(1,700)
Amortization of acquisition-related intangibles	75,879	34,693	23,763
Gains on sale of assets	(1,177)	(184)	(10,836)
Operating Profit	583,882	552,630	552,955
Interest expense	132,558	65,363	52,989
Loss on extinguishment of debt	38,810	0	0
Other income, net	(35,243)	(49,778)	(23,751)
Income before taxes	447,757	537,045	523,717
Taxes on income	107,976	241,380	118,686
Net income	339,781	295,665	405,031
Net income attributable to noncontrolling interests	2,479	0	0
Net income available to IFF common shareholders	337,302	295,665	405,031
Other comprehensive income (loss):
Foreign currency translation adjustments	(99,580)	54,609	(54,526)
Gains (losses) on derivatives qualifying as hedges	15,078	(17,936)	(1,797)
Pension and postretirement liability adjustment	19,757	5,940	(10,332)
Comprehensive income attributable to IFF stockholders	$ 272,557	$ 338,278	$ 338,376
Net income per share - basic (in dollars per share)	$ 3.81	$ 3.73	$ 5.07
Net income per share - diluted (in dollars per share)	$ 3.79	$ 3.72	$ 5.05
Average number of shares outstanding - basic (in shares)	87,551	79,070	79,648
Average number of shares outstanding - diluted (in shares)	88,121	79,370	79,981