CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 7,135	$ 3,565
Short-term investments	2,760	2,691
Accounts receivable	25,116	23,029
Inventories	75,000	82,307
Prepaid expenses and other current assets	2,503	3,173
Total current assets	112,514	114,765
Long-term investments	8,853	8,165
Property, plant and equipment	289,054	286,445
Less accumulated depreciation and amortization	164,446	161,098
Property plant and equipment net	124,608	125,347
Other assets and deferred charges:
Patents and licenses	1,043	1,072
Goodwill	9,730	9,730
Other	1,879	1,746
Total other assets and deferred charges	12,652	12,548
Total assets	258,627	260,825
Current liabilities:
Accounts payable and accrued liabilities	11,112	12,515
Accrued income and other taxes	1,140	106
Total current liabilities	12,252	12,621
Other non-current liabilities	4,452	5,315
Stockholders' equity:
Common stock, par value $0.10 per share; authorized 10,000 shares, issued 3,420 shares	342	342
Additional paid-in capital	67,472	67,331
Retained earnings	380,665	381,754
Treasury shares,1,660 at March 31, 2024 and 1,660 at December 31, 2023, at cost	(206,556)	(206,538)
Total stockholders' equity	241,923	242,889
Total liabilities and stockholders' equity	$ 258,627	$ 260,825