Segment Information, Revenue from External Customers by Geographic Markets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenue [Abstract]
Revenue	$ 339,186	$ 363,041	$ 686,699	$ 719,518
North America [Member]
Revenue [Abstract]
Revenue	178,453	190,934	357,232	373,571
Europe [Member]
Revenue [Abstract]
Revenue	80,112	86,115	170,289	175,179
Asia Pacific [Member]
Revenue [Abstract]
Revenue	53,264	56,994	105,564	110,937
Other [Member]
Revenue [Abstract]
Revenue	27,357	28,998	53,614	59,831
Flavors & Fragrances [Member]
Revenue [Abstract]
Revenue	174,534	191,818	353,278	374,300
Color [Member]
Revenue [Abstract]
Revenue	135,650	140,702	275,900	284,430
Asia Pacific [Member]
Revenue [Abstract]
Revenue	29,002	30,521	57,521	60,788
Reportable Geographical Components [Member] | Flavors & Fragrances [Member] | North America [Member]
Revenue [Abstract]
Revenue	113,115	127,196	225,862	246,251
Reportable Geographical Components [Member] | Flavors & Fragrances [Member] | Europe [Member]
Revenue [Abstract]
Revenue	41,323	44,964	89,324	90,391
Reportable Geographical Components [Member] | Flavors & Fragrances [Member] | Asia Pacific [Member]
Revenue [Abstract]
Revenue	9,430	9,069	17,039	16,091
Reportable Geographical Components [Member] | Flavors & Fragrances [Member] | Other [Member]
Revenue [Abstract]
Revenue	10,666	10,589	21,053	21,567
Reportable Geographical Components [Member] | Color [Member] | North America [Member]
Revenue [Abstract]
Revenue	65,301	63,738	131,308	127,320
Reportable Geographical Components [Member] | Color [Member] | Europe [Member]
Revenue [Abstract]
Revenue	38,682	41,127	80,817	84,758
Reportable Geographical Components [Member] | Color [Member] | Asia Pacific [Member]
Revenue [Abstract]
Revenue	15,112	17,641	31,537	34,551
Reportable Geographical Components [Member] | Color [Member] | Other [Member]
Revenue [Abstract]
Revenue	16,555	18,196	32,238	37,801
Reportable Geographical Components [Member] | Asia Pacific [Member] | North America [Member]
Revenue [Abstract]
Revenue	37	0	62	0
Reportable Geographical Components [Member] | Asia Pacific [Member] | Europe [Member]
Revenue [Abstract]
Revenue	107	24	148	30
Reportable Geographical Components [Member] | Asia Pacific [Member] | Asia Pacific [Member]
Revenue [Abstract]
Revenue	28,722	30,284	56,988	60,295
Reportable Geographical Components [Member] | Asia Pacific [Member] | Other [Member]
Revenue [Abstract]
Revenue	$ 136	$ 213	$ 323	$ 463