CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 16,437	$ 32,264
Short-term investments	34,146	29,059
Accounts receivable	27,539	21,023
Inventories	54,281	50,778
Prepaid expenses and other current assets	5,171	3,447
Total Current Assets	137,574	136,571
Long-term investments	15,794	19,423
Property, plant and equipment	249,648	233,217
Less accumulated depreciation and amortization	140,842	135,245
Total Property, Plant And Equipment	108,806	97,972
Other assets and deferred charges:
Patents	1,242	1,302
Goodwill	9,730	9,730
Other	2,171	2,266
Total Other Assets	13,143	13,298
Total assets	275,317	267,264
Current liabilities:
Accounts payable and accrued liabilities	17,861	13,076
Accrued income and other taxes	1,412	270
Total Current Liabilities	19,273	13,346
Line of credit	0	0
Other non-current liabilities	9,589	9,622
Stockholders' equity:
Common stock, par value $0.10 per share; authorized 10,000 shares, issued 3,420 shares	342	342
Paid-in capital	66,167	61,174
Retained earnings	368,165	357,324
Treasury shares,1,632 at June 30, 2022 and 1,619 at December 31, 2021, at cost	(188,219)	(174,544)
Total stockholders' equity	246,455	244,296
Total liabilities and stockholders' equity	$ 275,317	$ 267,264