Segment Information, Revenue from External Customers by Product Line (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
Flavors & Fragrances [Member]
Revenue [Abstract]
Revenue	191,818	180,736	374,300	361,811
Flavors [Member]
Revenue [Abstract]
Revenue	115,222	115,535	224,273	229,152
Natural Ingredients [Member]
Revenue [Abstract]
Revenue	56,197	48,998	109,398	102,520
Fragrances [Member]
Revenue [Abstract]
Revenue	27,239	21,023	53,333	40,759
Color [Member]
Revenue [Abstract]
Revenue	140,702	129,253	284,430	260,093
Food & Beverage Colors [Member]
Revenue [Abstract]
Revenue	77,467	70,496	154,283	141,884
Cosmetics [Member]
Revenue [Abstract]
Revenue	40,727	36,889	86,231	74,348
Other Colors [Member]
Revenue [Abstract]
Revenue	26,097	25,509	50,937	50,728
Asia Pacific [Member]
Revenue [Abstract]
Revenue	30,521	28,486	60,788	57,968
Intersegment Revenue [Member]
Revenue [Abstract]
Revenue	(10,429)	(8,920)	(19,725)	(18,100)
Intersegment Revenue [Member] | Flavors & Fragrances [Member]
Revenue [Abstract]
Revenue	(6,840)	(4,820)	(12,704)	(10,620)
Intersegment Revenue [Member] | Color [Member]
Revenue [Abstract]
Revenue	(3,589)	(3,641)	(7,021)	(6,867)
Intersegment Revenue [Member] | Asia Pacific [Member]
Revenue [Abstract]
Revenue	$ 0	$ (459)	$ 0	$ (613)