Note 13 - Income Taxes - Reconciliation of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income taxes computed at the federal statutory rate	$ 21,938	$ 30,701	$ 9,325
State taxes, net of federal benefits	1,210	1,422	796
State tax rate changes, net of federal benefits	350	(546)	(2,274)
Percentage depletion	(1,717)	(3,314)	(3,363)
Stock-based compensation	(3,395)	(1,499)	(194)
162(m) compensation limitation	5,716	3,481
Foreign-derived intangible income deduction	(1,475)
Other, net	(277)	(92)	357
Total income tax expense, net	$ 22,350	$ 30,153	$ 4,647