Segment Information, Operating Results by Segment (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue [Abstract]
Revenue	$ 342,734	$ 353,519	$ 1,062,252	$ 1,033,391
Operating income (loss)	50,264	52,010	158,126	120,427
Interest expense	5,407	4,946	16,517	14,474
Earnings before income taxes	44,857	47,064	141,609	105,953
Flavors & Fragrances [Member]
Revenue [Abstract]
Revenue	179,103	191,063	553,403	552,874
Operating income (loss)	24,814	33,006	74,142	90,278
Interest expense	0	0	0	0
Earnings before income taxes	24,814	33,006	74,142	90,278
Color [Member]
Revenue [Abstract]
Revenue	132,187	129,899	416,617	389,992
Operating income (loss)	27,269	28,624	92,074	87,913
Interest expense	0	0	0	0
Earnings before income taxes	27,269	28,624	92,074	87,913
Asia Pacific [Member]
Revenue [Abstract]
Revenue	31,275	32,557	92,063	90,525
Operating income (loss)	5,750	5,780	15,256	14,750
Interest expense	0	0	0	0
Earnings before income taxes	5,750	5,780	15,256	14,750
Reportable Segments [Member]
Revenue [Abstract]
Revenue	350,802	361,923	1,090,045	1,059,895
Reportable Segments [Member] \| Flavors & Fragrances [Member]
Revenue [Abstract]
Revenue	184,397	195,992	571,401	568,423
Reportable Segments [Member] \| Color [Member]
Revenue [Abstract]
Revenue	134,961	133,223	426,412	400,183
Reportable Segments [Member] \| Asia Pacific [Member]
Revenue [Abstract]
Revenue	31,275	32,708	92,063	91,289
Intersegment Revenue [Member]
Revenue [Abstract]
Revenue	(8,068)	(8,404)	(27,793)	(26,504)
Intersegment Revenue [Member] \| Flavors & Fragrances [Member]
Revenue [Abstract]
Revenue	(5,294)	(4,929)	(17,998)	(15,549)
Intersegment Revenue [Member] \| Color [Member]
Revenue [Abstract]
Revenue	(2,774)	(3,324)	(9,795)	(10,191)
Intersegment Revenue [Member] \| Asia Pacific [Member]
Revenue [Abstract]
Revenue	0	(151)	0	(764)
Corporate & Other [Member]
Revenue [Abstract]
Revenue	169	0	169	0
Operating income (loss)	(7,569)	(15,400)	(23,346)	(72,514)
Interest expense	5,407	4,946	16,517	14,474
Earnings before income taxes	$ (12,976)	$ (20,346)	$ (39,863)	$ (86,988)

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