Equity Investment - Schedule of Summarized Financial Information of Unaudited Financial Statements (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Schedule of Equity Method Investments [Line Items]
Net sales			$ 3,214	$ 23,015
Ciner Wyoming
Schedule of Equity Method Investments [Line Items]
Net sales	$ 76,184	$ 129,794	190,607	260,230
Gross profit	2,242	32,533	23,659	66,635
Net income (loss)	$ (4,177)	$ 25,610	$ 11,115	$ 51,925