Segment Information, Revenue from External Customers by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue [Abstract]
Revenue	$ 317,650	$ 342,734	$ 1,004,349	$ 1,062,252
Flavors [Member]
Revenue [Abstract]
Revenue	89,604	98,060	295,375	322,333
Natural Ingredients [Member]
Revenue [Abstract]
Revenue	53,220	58,140	156,864	167,538
Fragrances [Member]
Revenue [Abstract]
Revenue	24,753	28,197	79,025	81,530
Food & Beverage Colors [Member]
Revenue [Abstract]
Revenue	73,383	76,524	233,121	230,807
Cosmetics [Member]
Revenue [Abstract]
Revenue	32,080	35,466	106,218	121,697
Other Colors [Member]
Revenue [Abstract]
Revenue	21,542	23,140	70,457	74,077
Asia Pacific [Member]
Revenue [Abstract]
Revenue	30,125	31,275	87,646	92,063
Flavors & Fragrances [Member]
Revenue [Abstract]
Revenue	163,870	179,103	517,148	553,403
Flavors & Fragrances [Member] | Flavors [Member]
Revenue [Abstract]
Revenue	89,604	98,060	295,375	322,333
Flavors & Fragrances [Member] | Natural Ingredients [Member]
Revenue [Abstract]
Revenue	53,220	58,140	156,864	167,538
Flavors & Fragrances [Member] | Fragrances [Member]
Revenue [Abstract]
Revenue	24,753	28,197	79,025	81,530
Color [Member]
Revenue [Abstract]
Revenue	123,710	132,356	399,610	416,786
Color [Member] | Food & Beverage Colors [Member]
Revenue [Abstract]
Revenue	73,383	76,524	233,121	230,807
Color [Member] | Cosmetics [Member]
Revenue [Abstract]
Revenue	32,080	35,466	106,218	121,697
Color [Member] | Other Colors [Member]
Revenue [Abstract]
Revenue	21,542	23,140	70,457	74,077
Asia Pacific [Member]
Revenue [Abstract]
Revenue	30,070	31,275	87,591	92,063
Asia Pacific [Member] | Asia Pacific [Member]
Revenue [Abstract]
Revenue	30,125	31,275	87,646	92,063
Intersegment Revenue [Member]
Revenue [Abstract]
Revenue	(7,057)	(8,068)	(24,357)	(27,793)
Intersegment Revenue [Member] | Flavors & Fragrances [Member]
Revenue [Abstract]
Revenue	(3,707)	(5,294)	(14,116)	(17,998)
Intersegment Revenue [Member] | Color [Member]
Revenue [Abstract]
Revenue	(3,295)	(2,774)	(10,186)	(9,795)
Intersegment Revenue [Member] | Asia Pacific [Member]
Revenue [Abstract]
Revenue	$ (55)	$ 0	$ (55)	$ 0