UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating activities
Net cash provided by (used for) operating activities	$ 6,254	$ (1,070)
Investing activities
Expenditures for property, plant and equipment and acquisition of mineral interests	(7,879)	(4,649)
Proceeds from the sale of property, plant and equipment	272	135
Proceeds from the sale of private company equity units	1,153	0
Other	(10)	(15)
Net cash used for investing activities	(6,464)	(4,529)
Financing activities
Additions to long-term debt	2,112	3,348
Reductions of long-term debt	(1,456)	(2,689)
Net additions to revolving credit agreements	0	2,000
Cash dividends paid	(1,557)	(1,445)
Net cash (used for) provided by financing activities	(901)	1,214
Cash and cash equivalents
Total decrease for the period	(1,111)	(4,385)
Balance at the beginning of the period	110,748	86,005
Balance at the end of the period	$ 109,637	$ 81,620