Unaudited Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
ASSETS
Cash and cash equivalents	$ 83,403	$ 101,600
Accounts receivable, net	14,004	14,611
Accounts receivable from affiliates	21,693	19,919
Inventories, net	30,115	30,015
Prepaid expenses and other	13,074	10,843
Total current assets	162,289	176,988
Property, plant and equipment, net	119,811	120,068
Intangibles, net	42,870	43,554
Deferred income taxes	4,465	5,962
Investments in unconsolidated subsidiaries	18,679	16,335
Deferred costs	3,555	3,582
Other non-current assets	22,507	23,063
Total assets	374,176	389,552
LIABILITIES AND EQUITY
Accounts payable	8,174	7,575
Accounts payable to affiliates	237	1,925
Revolving credit agreements	15,000	15,000
Current maturities of long-term debt	1,081	1,125
Accrued payroll	6,010	17,204
Asset retirement obligations	3,092	3,092
Other current liabilities	7,245	8,055
Total current liabilities	40,839	53,976
Long-term debt	34,687	42,021
Asset retirement obligations	35,907	37,005
Pension and other postretirement obligations	11,293	11,827
Deferred compensation	12,939	12,939
Other long-term liabilities	13,629	12,336
Total liabilities	149,294	170,104
Common stock:
Capital in excess of par value	4,537	4,447
Retained earnings	226,513	216,490
Accumulated other comprehensive loss	(13,107)	(8,341)
Total stockholders' equity	224,882	219,448
Total liabilities and equity	374,176	389,552
Shares Outstanding Class A
Common stock:
Common stock	5,369	5,282
Shares Outstanding Class B
Common stock:
Common stock	$ 1,570	$ 1,570