Net Sales - Summary of Net Sales Disaggregated by Principal Markets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net sales:
Net sales	$ 98,116	$ 83,411
Chemical [Member]
Net sales:
Net sales	98,116	83,411
Chemical [Member] | Agricultural Products [Member]
Net sales:
Net sales	44,913	41,458
Chemical [Member] | Industrial Acids and Other Chemical Products [Member]
Net sales:
Net sales	40,275	35,206
Chemical [Member] | Mining Products [Member]
Net sales:
Net sales	$ 12,928	$ 6,747