Business Segments - Schedule of Operating Results and Certain Other Financial Data for Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Revenues	$ 10,850	$ 10,477	$ 21,156	$ 20,610
Operating profit (loss)	4,542	5,372	9,444	10,296
General and administrative expenses	2,885	2,552	5,462	4,594
Total operating profit	1,657	2,820	3,982	5,702
Interest expense	824	829	1,519	1,740
Depreciation, depletion and amortization			5,622	5,210
Capital expenditures	6,061	6,313	9,161	12,518
Operating Segments
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	2,726	2,543	5,333	5,078
Operating Segments | Industrial and commercial
Segment Reporting Information [Line Items]
Revenues	1,374	1,445	2,721	2,898
Operating profit (loss)	443	830	1,086	1,642
Depreciation, depletion and amortization	571	360	962	723
Capital expenditures	38	248	138	393
Operating Segments | Mining royalty lands
Segment Reporting Information [Line Items]
Revenues	3,609	3,231	6,843	6,194
Operating profit (loss)	3,340	2,985	6,305	5,709
Depreciation, depletion and amortization	177	159	355	308
Capital expenditures	180	22	228	42
Operating Segments | Development
Segment Reporting Information [Line Items]
Revenues	300	305	601	608
Operating profit (loss)	(698)	137	(613)	77
Depreciation, depletion and amortization	43	43	86	85
Capital expenditures	5,524	5,927	8,174	11,881
Operating Segments | Multifamily
Segment Reporting Information [Line Items]
Revenues	5,567	5,496	10,991	10,910
Operating profit (loss)	1,457	1,420	2,666	2,868
Depreciation, depletion and amortization	1,935	1,981	3,930	3,962
Capital expenditures	$ 319	$ 116	$ 621	$ 202