Net Sales

6 Months Ended

Jun. 30, 2021

Revenue From Contract With Customer [Abstract]

Net Sales

9.  Net Sales

Disaggregated Net Sales

As discussed in Note 1, we primarily derive our revenues from the sales of various chemical products.  The following table presents our net sales disaggregated by our principal markets, which disaggregation is consistent with other financial information utilized or provided outside of our condensed consolidated financial statements:

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
	(In Thousands)
Net sales:
Agricultural products	$	66,508	$	64,997	$	111,421	$	106,455
Industrial acids and other chemical products		60,608		29,559		100,883		64,765
Mining products		13,580		10,477		26,508		17,224
Total net sales	$	140,696	$	105,033	$	238,812	$	188,444

Other Information

Although most of our contracts have an original expected duration of one year or less, for our contracts with a duration greater than one year at contract inception, the average remaining expected duration was approximately 15 months at June 30, 2021.

Liabilities associated with contracts with customers (contract liabilities) primarily relate to deferred revenue and customer deposits associated with cash payments received in advance from customers for volume shortfall charges and product shipments.  We had approximately $1.2 million and $2.5 million of contract liabilities as of June 30, 2021 and December 31, 2020, respectively.  For the three and six months ended June 30, 2021, revenues of $1.0 million and $1.6 million, respectively, were recognized and included in the balance at the beginning of the respective period. For the three and six months ended June 30, 2020, revenues of $1.5 million and $1.0 million, respectively, were recognized and included in the balance at the beginning of the respective period.