Segment Information - Reportable Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net sales:
Net sales	$ 907,548	$ 872,940	$ 2,758,492	$ 2,544,094
Segment profit:
Restructuring and other charges, net	(927)	(3,249)	(2,830)	(14,183)
Gain on sales of fixed assets	1,630	31	435	120
Operating profit	159,268	149,000	488,633	430,750
Interest expense	(23,914)	(19,221)	(93,755)	(49,584)
Loss on extinguishment of debt	(38,810)	0	(38,810)	0
Other income, net	4,158	11,547	25,389	40,687
Income before taxes	100,702	141,326	381,457	421,853
Flavor Compounds
Net sales:
Net sales	436,214	409,800	1,335,773	1,230,286
Segment profit:
Operating profit	96,497	87,375	317,666	278,768
Fragrances [Member]
Net sales:
Net sales	471,334	463,140	1,422,719	1,313,808
Segment profit:
Operating profit	87,488	88,959	261,545	247,824
Global expenses [Member]
Segment profit:
Operating profit	(19,578)	(17,693)	(63,975)	(47,472)
Corporate and Other [Member]
Segment profit:
Restructuring and other charges, net	(344)	(407)	(1,773)	(1,473)
Operational improvement initiative costs	(958)	(580)	(1,951)	(2,501)
Legal Charges/Credits, net	0	0	0	(1,000)
Gain on sales of fixed assets	0	0	0	(5,331)
Tax assessment	(927)	(3,249)	(1,837)	(14,183)
Integration-related costs	1,630	31	435	120
FDA mandated product recall	(9,800)	0	(4,800)	3,500
Acquisition Related Costs | Corporate and Other [Member]
Segment profit:
Acquisition and related costs	1	(5,436)	519	(20,502)
Frutarom Acquisition Related Costs
Segment profit:
Interest expense			(38,800)
Loss on extinguishment of debt			(38,800)
Frutarom Acquisition Related Costs | Corporate and Other [Member]
Segment profit:
Acquisition and related costs	$ (14,341)	$ 0	$ (26,796)	$ 0