Segment Information, Revenue from External Customers by Geographic Markets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue [Abstract]
Revenue	$ 363,041	$ 338,475	$ 719,518	$ 679,872
North America [Member]
Revenue [Abstract]
Revenue	190,934	181,030	373,571	364,886
Europe [Member]
Revenue [Abstract]
Revenue	86,115	80,265	175,179	159,156
Asia Pacific [Member]
Revenue [Abstract]
Revenue	56,994	49,797	110,937	100,215
Other [Member]
Revenue [Abstract]
Revenue	28,998	27,383	59,831	55,615
Flavors & Fragrances [Member]
Revenue [Abstract]
Revenue	191,818	180,736	374,300	361,811
Color [Member]
Revenue [Abstract]
Revenue	140,702	129,253	284,430	260,093
Asia Pacific [Member]
Revenue [Abstract]
Revenue	30,521	28,486	60,788	57,968
Asia Pacific [Member] | Asia Pacific [Member]
Revenue [Abstract]
Revenue	30,521	28,486	60,788	57,968
Reportable Geographical Components [Member] | Flavors & Fragrances [Member] | North America [Member]
Revenue [Abstract]
Revenue	127,196	121,727	246,251	243,849
Reportable Geographical Components [Member] | Flavors & Fragrances [Member] | Europe [Member]
Revenue [Abstract]
Revenue	44,964	42,414	90,391	84,921
Reportable Geographical Components [Member] | Flavors & Fragrances [Member] | Asia Pacific [Member]
Revenue [Abstract]
Revenue	9,069	6,798	16,091	13,122
Reportable Geographical Components [Member] | Flavors & Fragrances [Member] | Other [Member]
Revenue [Abstract]
Revenue	10,589	9,797	21,567	19,919
Reportable Geographical Components [Member] | Color [Member] | North America [Member]
Revenue [Abstract]
Revenue	63,738	59,303	127,320	121,037
Reportable Geographical Components [Member] | Color [Member] | Europe [Member]
Revenue [Abstract]
Revenue	41,127	37,787	84,758	74,110
Reportable Geographical Components [Member] | Color [Member] | Asia Pacific [Member]
Revenue [Abstract]
Revenue	17,641	15,023	34,551	29,801
Reportable Geographical Components [Member] | Color [Member] | Other [Member]
Revenue [Abstract]
Revenue	18,196	17,140	37,801	35,145
Reportable Geographical Components [Member] | Asia Pacific [Member] | North America [Member]
Revenue [Abstract]
Revenue	0	0	0	0
Reportable Geographical Components [Member] | Asia Pacific [Member] | Europe [Member]
Revenue [Abstract]
Revenue	24	64	30	125
Reportable Geographical Components [Member] | Asia Pacific [Member] | Asia Pacific [Member]
Revenue [Abstract]
Revenue	30,284	27,976	60,295	57,292
Reportable Geographical Components [Member] | Asia Pacific [Member] | Other [Member]
Revenue [Abstract]
Revenue	$ 213	$ 446	$ 463	$ 551