CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Current assets:
Cash and cash equivalents	$ 319,910	$ 278,031
Trade receivables, net	54,392	43,982
Inventories	25,595	27,686
Prepaid expenses and other current assets	3,549	5,083
Total current assets	403,446	354,782
Property, plant and equipment	520,832	493,246
Less accumulated depreciation and depletion	(321,609)	(310,355)
Property, plant and equipment, net	199,223	182,891
Operating lease right-of-use assets	4,295	4,855
Other assets, net	458	635
Total assets	607,422	543,163
Current liabilities:
Accounts payable	11,099	8,819
Current portion of operating lease liabilities	1,588	1,602
Accrued expenses	5,861	6,541
Total current liabilities	18,548	16,962
Deferred tax liabilities, net	21,370	23,659
Operating lease liabilities, excluding current portion	2,890	3,437
Other liabilities	1,323	1,364
Total liabilities	44,131	45,422
Stockholders' equity:
Common stock	2,970	2,968
Additional paid-in capital	45,014	40,549
Retained earnings	577,129	515,622
Less treasury stock, at cost	(61,822)	(61,398)
Total stockholders' equity	563,291	497,741
Total liabilities and stockholders' equity	$ 607,422	$ 543,163