Unaudited Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
ASSETS
Cash and cash equivalents	$ 85,012	$ 88,450
Trade accounts receivable, net	21,277	18,894
Accounts receivable from affiliates	6,933	4,764
Inventories	49,716	47,551
Federal income tax receivable	9,334	17,615
Prepaid insurance	7,977	2,564
Other current assets	9,064	8,308
Total current assets	189,313	188,146
Property, plant and equipment, net	175,553	172,417
Intangibles, net	33,437	35,330
Investments in unconsolidated subsidiaries	20,927	28,978
Operating lease right-of-use assets	9,594	10,324
Other non-current assets	45,215	40,984
Total assets	474,039	476,179
LIABILITIES AND EQUITY
Accounts payable	9,889	5,522
Accounts payable to affiliates	517	125
Revolving credit agreements	9,000	20,000
Current maturities of long-term debt	1,168	2,112
Asset retirement obligations	1,844	1,844
Accrued payroll	9,200	14,430
Other current liabilities	8,807	8,224
Total current liabilities	40,425	52,257
Long-term debt	21,805	24,353
Operating lease liabilities	10,479	11,196
Asset retirement obligations	41,095	39,888
Pension and other postretirement obligations	7,847	8,838
Deferred income taxes	14,784	17,550
Liability for uncertain tax positions	9,413	9,413
Other long-term liabilities	12,464	12,060
Total liabilities	158,312	175,555
Common stock:
Capital in excess of par value	12,928	10,895
Retained earnings	306,950	294,270
Accumulated other comprehensive loss	(11,313)	(11,599)
Total stockholders' equity	315,727	300,624
Total liabilities and equity	474,039	476,179
Class A Common Stock
Common stock:
Common stock	5,595	5,490
Class B Common Stock
Common stock:
Common stock	$ 1,567	$ 1,568