Customer Claims - Additional Information (Detail) - Surfactants [Member]	3 Months Ended		12 Months Ended
	Dec. 31, 2017 USD ($) Claim	Dec. 31, 2016 Claim	Dec. 31, 2016 USD ($)
Loss Contingencies [Line Items]
Number of customer claims | Claim		2
Insurance claims reserve amount			$ 7,367,000
Claim paid	$ 2,709,000
Number of claims and reversed | Claim	1
Claims and reversed remainder of claim realizing income	$ 4,660,000