CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
ASSETS
Cash and cash equivalents	$ 590,619	$ 510,834
Accounts receivable and accrued receivables, net	106,044	103,983
Prepaid expenses and other current assets	7,586	7,427
Tax like-kind exchange escrow	6,757	6,348
Prepaid income taxes	0	4,809
Total current assets	711,006	633,401
Real estate acquired	109,704	109,704
Property, plant and equipment, net	86,192	85,478
Royalty interests acquired, net	44,720	45,025
Other assets	3,629	3,819
Real estate and royalty interests assigned through the 1888 Declaration of Trust, no value assigned:
Total assets	955,251	877,427
LIABILITIES AND EQUITY
Accounts payable and accrued expenses	27,263	23,443
Ad valorem and other taxes payable	4,560	8,497
Income taxes payable	22,430	3,167
Unearned revenue	6,784	4,488
Total current liabilities	61,037	39,595
Deferred taxes payable	40,845	41,151
Unearned revenue - noncurrent	22,395	21,708
Accrued liabilities - noncurrent	1,923	2,086
Total liabilities	126,200	104,540
Commitments and contingencies	0	0
Equity:
Preferred stock, $0.01 par value; 1,000,000 shares authorized, none outstanding as of March 31, 2023 and December 31, 2022	0	0
Common stock, $0.01 par value; 7,756,156 shares authorized and 7,693,320 and 7,695,679 outstanding as of March 31, 2023 and December 31, 2022, respectively	78	78
Treasury stock, at cost; 62,836 and 60,477 shares as of March 31, 2023 and December 31, 2022, respectively	(108,794)	(104,139)
Additional paid-in capital	7,733	8,293
Accumulated other comprehensive income	2,491	2,516
Retained earnings	927,543	866,139
Total equity	829,051	772,887
Total liabilities and equity	955,251	877,427
Land (surface rights)
Real estate and royalty interests assigned through the 1888 Declaration of Trust, no value assigned:
Land (surface rights)	0	0
1/16th nonparticipating perpetual royalty interest
Real estate and royalty interests assigned through the 1888 Declaration of Trust, no value assigned:
1/16th nonparticipating perpetual royalty interest	0	0
1/128th nonparticipating perpetual royalty interest
Real estate and royalty interests assigned through the 1888 Declaration of Trust, no value assigned:
1/128th nonparticipating perpetual royalty interest	$ 0	$ 0