CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Current assets:
Cash and cash equivalents	$ 300,634	$ 278,031
Trade receivables, net	55,772	43,982
Inventories	27,860	27,686
Prepaid expenses and other current assets	4,071	5,083
Total current assets	388,337	354,782
Property, plant and equipment	507,950	493,246
Less accumulated depreciation and depletion	(316,140)	(310,355)
Property, plant and equipment, net	191,810	182,891
Operating lease right-of-use assets	4,643	4,855
Other assets, net	465	635
Total assets	585,255	543,163
Current liabilities:
Accounts payable	9,233	8,819
Current portion of operating lease liabilities	1,602	1,602
Accrued expenses	14,556	6,541
Total current liabilities	25,391	16,962
Deferred tax liabilities, net	23,088	23,659
Operating lease liabilities, excluding current portion	3,226	3,437
Other liabilities	1,343	1,364
Total liabilities	53,048	45,422
Stockholders' equity:
Common stock	2,969	2,968
Additional paid-in capital	43,044	40,549
Retained earnings	548,016	515,622
Less treasury stock, at cost	(61,822)	(61,398)
Total stockholders' equity	532,207	497,741
Total liabilities and stockholders' equity	$ 585,255	$ 543,163