Segment Information, Revenue from External Customers by Product Line (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
Flavors & Fragrances [Member]
Revenue [Abstract]
Revenue	174,534	191,818	353,278	374,300
Flavors [Member]
Revenue [Abstract]
Revenue	101,495	115,222	205,771	224,273
Natural Ingredients [Member]
Revenue [Abstract]
Revenue	52,425	56,197	103,644	109,398
Fragrances [Member]
Revenue [Abstract]
Revenue	26,214	27,239	54,272	53,333
Color [Member]
Revenue [Abstract]
Revenue	135,650	140,702	275,900	284,430
Food & Beverage Colors [Member]
Revenue [Abstract]
Revenue	79,374	77,467	159,738	154,283
Cosmetics [Member]
Revenue [Abstract]
Revenue	35,855	40,727	74,138	86,231
Other Colors [Member]
Revenue [Abstract]
Revenue	23,683	26,097	48,915	50,937
Asia Pacific [Member]
Revenue [Abstract]
Revenue	29,002	30,521	57,521	60,788
Intersegment Revenue [Member]
Revenue [Abstract]
Revenue	(8,862)	(10,429)	(17,300)	(19,725)
Intersegment Revenue [Member] | Flavors & Fragrances [Member]
Revenue [Abstract]
Revenue	(5,600)	(6,840)	(10,409)	(12,704)
Intersegment Revenue [Member] | Color [Member]
Revenue [Abstract]
Revenue	(3,262)	(3,589)	(6,891)	(7,021)
Intersegment Revenue [Member] | Asia Pacific [Member]
Revenue [Abstract]
Revenue	$ 0	$ 0	$ 0	$ 0