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Restructuring and Other Charges, Net - Changes in Employee-Related Restructuring Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2017
Restructuring Reserve [Roll Forward]
Beginning Balance			$ 21,085
Additional Charges (Reversals), Net			8,299
Non-Cash Charges			4,276
Additional charges, net	$ 1,497	$ 3,716	8,299	$ 22,415
Payments			(9,215)
Ending Balance	15,893		15,893		$ 21,085
2017 Productivity Program
Restructuring Reserve [Roll Forward]
Additional charges, net						$ 24,500
2017 Productivity Program \| Employee Severance
Restructuring Reserve [Roll Forward]
Beginning Balance			1,106
Additional Charges (Reversals), Net			0
Non-Cash Charges			0
Payments			(277)
Ending Balance	829		829		1,106
2017 Productivity Program \| Other
Restructuring Reserve [Roll Forward]
Beginning Balance			88
Additional Charges (Reversals), Net			0
Non-Cash Charges			0
Payments			0
Ending Balance	88		88		88
Frutarom Integration Initiative \| Employee Severance
Restructuring Reserve [Roll Forward]
Beginning Balance			4,038
Additional Charges (Reversals), Net			2,003
Non-Cash Charges			0
Additional charges, net			18,300
Payments			(3,221)
Ending Balance	2,820		2,820		4,038
Frutarom Integration Initiative \| Fixed Asset Write Down [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance			0
Additional Charges (Reversals), Net			4,647
Non-Cash Charges			4,647
Payments			0
Ending Balance	0		0		0
Frutarom Integration Initiative \| Other
Restructuring Reserve [Roll Forward]
Beginning Balance			2,485
Additional Charges (Reversals), Net			1,291
Non-Cash Charges			371
Payments			(812)
Ending Balance	3,335		3,335		2,485
2019 Severance Initiatives \| Employee Severance
Restructuring Reserve [Roll Forward]
Beginning Balance			12,897
Additional Charges (Reversals), Net			358
Non-Cash Charges			0
Additional charges, net					21,700
Payments			(4,905)
Ending Balance	8,350		8,350		12,897
2019 Severance Initiatives \| Other
Restructuring Reserve [Roll Forward]
Beginning Balance			471
Additional Charges (Reversals), Net			0
Non-Cash Charges			0
Payments			0
Ending Balance	471		471		$ 471
Taste
Restructuring Reserve [Roll Forward]
Additional charges, net	1,139	2,541	7,941	7,618
Scent [Member]
Restructuring Reserve [Roll Forward]
Additional charges, net	358	803	358	11,703
Shared IT & Corporate Costs [Member]
Restructuring Reserve [Roll Forward]
Additional charges, net	$ 0	$ 372	$ 0	$ 3,094