CONSOLIDATED STATEMENT OF INCOME AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net sales	$ 1,267,345	$ 907,548	$ 3,856,315	$ 2,758,492
Cost of goods sold	734,257	506,882	2,245,729	1,553,300
Gross profit	533,088	400,666	1,610,586	1,205,192
Research and development expenses	85,077	75,302	260,489	228,545
Selling and administrative expenses	210,829	157,796	634,111	457,847
Amortization of acquisition-related intangibles	48,430	9,003	143,964	27,772
Restructuring and other charges, net	3,716	927	22,415	2,830
Losses (gains) on sales of fixed assets	372	(1,630)	1,136	(435)
Operating profit	184,664	159,268	548,471	488,633
Interest expense	33,497	23,914	102,662	93,755
Loss on extinguishment of debt	0	38,810	0	38,810
Other income, net	(5,699)	(4,158)	(15,114)	(25,389)
Income before taxes	156,866	100,702	460,923	381,457
Taxes on income	27,059	4,986	81,033	57,176
Net income	129,807	95,716	379,890	324,281
Net income attributable to noncontrolling interests	2,683	0	7,560	0
Net income attributable to IFF stockholders	127,124	95,716	372,330	324,281
Other comprehensive loss, after tax:
Foreign currency translation adjustments	(204,853)	(27,587)	(176,490)	(98,048)
Gains on derivatives qualifying as hedges	2,939	2,421	3,257	12,347
Pension and postretirement net liability	2,721	2,559	7,908	8,078
Net current period other comprehensive income (loss)	(199,193)	(22,607)	(165,325)	(77,623)
Comprehensive (loss) income attributable to IFF stockholders	$ (72,069)	$ 73,109	$ 207,005	$ 246,658
Net income per share - basic (in dollars per share)	$ 1.15	$ 1.18	$ 3.34	$ 4.06
Net income per share - diluted (in dollars per share)	$ 1.13	$ 1.17	$ 3.30	$ 4.04
Average number of shares outstanding - basic (in shares)	111,998	81,263	111,953	79,783
Average number of shares outstanding - diluted (in shares)	113,493	81,647	113,133	80,115