Business Restructuring - Additional Information (Detail)	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2019 USD ($) Employees	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Restructuring Cost And Reserve [Line Items]
Business restructuring	$ 450,000		$ 273,000		$ 1,183,000	$ 631,000
Netherlands [Member]
Restructuring Cost And Reserve [Line Items]
Number positions eliminated | Employees					5
Severance costs					$ 396,000
Germany [Member] | Surfactants [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring costs					$ 1,799,000
Germany [Member] | Surfactants [Member] | Asset and Spare Part [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring costs							$ 1,404,000
Fieldsboro, NJ [Member]
Restructuring Cost And Reserve [Line Items]
Business restructuring		$ 251,000		$ 915,000
Longford Mills [Member] | Surfactants [Member]
Restructuring Cost And Reserve [Line Items]
Number positions eliminated | Employees					30
Business restructuring					$ 6,595,000
Decommissioning expense	200,000
Termination Benefits [Member] | Netherlands [Member]
Restructuring Cost And Reserve [Line Items]
Business restructuring					122,000
Termination Benefits [Member] | Longford Mills [Member] | Surfactants [Member]
Restructuring Cost And Reserve [Line Items]
Business restructuring	$ 50,000				1,644,000
Decommissioning Costs [Member] | Germany [Member] | Surfactants [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring costs					395,000
Other Expense [Member] | Longford Mills [Member] | Surfactants [Member]
Restructuring Cost And Reserve [Line Items]
Business restructuring					$ 4,951,000