Net Sales - Summary of Net Sales Disaggregated by Principal Markets (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Net sales:
Net sales	$ 83,411	$ 94,152
Chemical [Member]
Net sales:
Net sales	83,411	94,152
Chemical [Member] \| Agricultural Products [Member]
Net sales:
Net sales	41,458	46,820
Chemical [Member] \| Industrial Acids and Other Chemical Products [Member]
Net sales:
Net sales	35,206	37,850
Chemical [Member] \| Mining Products [Member]
Net sales:
Net sales	$ 6,747	$ 9,482

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration