Net Sales

12 Months Ended

Dec. 31, 2020

Revenue From Contract With Customer [Abstract]

Net Sales

16. 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 consolidated financial statements:

	2020		2019		2018
	(Dollars In Thousands)
Net sales:
Agricultural products	$	180,036	$	187,641	$	187,164
Industrial products		133,024		139,643		148,598
Mining products		38,256		37,786		42,398
Total net sales	$	351,316	$	365,070	$	378,160

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 17 months at December 31, 2020.

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 $2.5 million and $3.6 million of contract liabilities as of December 31, 2020 and 2019, respectively.  During 2020, revenues of $1.9 million were recognized and included in the balance at the beginning of the period.