UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
ASSETS
Cash and cash equivalents	$ 109,637	$ 110,748
Trade accounts receivable	31,039	37,940
Accounts receivable from affiliates	4,476	6,638
Inventories	71,246	71,488
Federal income tax receivable	15,098	15,687
Prepaid insurance	11,840	1,999
Other current assets	12,918	15,907
Total current assets	256,254	260,407
Property, plant and equipment, net	219,772	217,952
Intangibles, net	27,328	28,055
Investments in unconsolidated subsidiaries	13,945	14,927
Operating lease right-of-use assets	6,221	6,419
Other non-current assets	38,604	40,312
Total assets	562,124	568,072
LIABILITIES AND EQUITY
Accounts payable	10,610	11,952
Accounts payable to affiliates	868	1,362
Current maturities of long-term debt	2,943	3,649
Asset retirement obligations	2,497	1,746
Accrued payroll	7,922	18,105
Deferred revenue	2,044	833
Other current liabilities	7,128	6,623
Total current liabilities	34,012	44,270
Long-term debt	17,434	16,019
Operating lease liabilities	7,278	7,528
Asset retirement obligations	46,418	44,256
Pension and other postretirement obligations	4,778	5,082
Deferred income taxes	3,701	6,122
Liability for uncertain tax positions	9,004	9,329
Other long-term liabilities	7,813	8,500
Total liabilities	130,438	141,106
Common stock:
Capital in excess of par value	24,109	23,706
Retained earnings	409,059	404,924
Accumulated other comprehensive loss	(8,992)	(9,013)
Total stockholders' equity	431,686	426,966
Total liabilities and equity	562,124	568,072
Class A Common Stock
Common stock:
Common stock	5,944	5,783
Class B Common Stock
Common stock:
Common stock	$ 1,566	$ 1,566