CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets
Cash and cash equivalents	$ 85,109	$ 110,748
Inventories	77,000	71,488
Assets held for sale	6,466	285
Federal income tax receivable	845	15,687
Prepaid insurance	1,790	1,999
Other current assets	15,499	15,622
Total current assets	231,998	260,407
Property, plant and equipment, net	223,902	217,952
Intangibles, net	6,006	28,055
Deferred income taxes	15,081	0
Investments in unconsolidated subsidiaries	12,371	14,927
Operating lease right-of-use assets	8,667	6,419
Other non-current assets	41,683	40,312
Total assets	539,708	568,072
Current liabilities
Revolving credit agreements	10,000	0
Current maturities of long-term debt	3,953	3,649
Asset retirement obligations	13,114	1,746
Accrued payroll	17,317	18,105
Deferred revenue	878	833
Other current liabilities	7,118	6,623
Total current liabilities	69,986	44,270
Long-term debt	22,003	16,019
Operating lease liabilities	8,782	7,528
Asset retirement obligations	39,499	44,256
Pension and other postretirement obligations	5,183	5,082
Deferred income taxes	0	6,122
Liability for uncertain tax positions	5,795	9,329
Other long-term liabilities	6,120	8,500
Total liabilities	157,368	141,106
Common stock:
Capital in excess of par value	28,672	23,706
Retained earnings	355,873	404,924
Accumulated other comprehensive loss	(9,654)	(9,013)
Total stockholders’ equity	382,340	426,966
Total liabilities and equity	539,708	568,072
Nonrelated Party
Current assets
Trade accounts receivable and accounts receivable from affiliates	37,429	37,940
Current liabilities
Accounts payable and accounts payable to affiliates	16,702	11,952
Affiliated Entity
Current assets
Trade accounts receivable and accounts receivable from affiliates	7,860	6,638
Current liabilities
Accounts payable and accounts payable to affiliates	904	1,362
Class A Common Stock
Common stock:
Common stock	5,883	5,783
Class B Common Stock
Common stock:
Common stock	$ 1,566	$ 1,566