Business Segments - Schedule of Operating Results and Certain Other Financial Data for Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Revenues	$ 10,633	$ 10,591	$ 31,243	$ 31,401
Operating profit (loss)	5,372	4,844	15,668	14,667
General and administrative expenses	2,289	1,948	6,883	6,150
Total operating profit (loss)	3,083	2,896	8,785	8,517
Interest expense	742	1,116	2,482	3,251
Depreciation, depletion and amortization			7,840	8,557
Capital expenditures	34,571	2,449	47,089	4,634
Operating Segments
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	2,551	2,816	7,629	8,415
Industrial and commercial | Operating Segments
Segment Reporting Information [Line Items]
Revenues	1,455	1,442	4,353	3,932
Operating profit (loss)	842	838	2,484	2,251
Depreciation, depletion and amortization	360	369	1,083	1,006
Capital expenditures	235	12	628	557
Mining royalty lands | Operating Segments
Segment Reporting Information [Line Items]
Revenues	3,199	3,082	9,393	9,628
Operating profit (loss)	2,946	2,745	8,655	8,781
Depreciation, depletion and amortization	163	138	471	472
Capital expenditures	18	0	60	0
Development | Operating Segments
Segment Reporting Information [Line Items]
Revenues	297	434	905	1,387
Operating profit (loss)	25	221	102	445
Depreciation, depletion and amortization	43	44	128	140
Capital expenditures	34,265	2,179	46,146	3,640
Multifamily | Operating Segments
Segment Reporting Information [Line Items]
Revenues	5,682	5,633	16,592	16,454
Operating profit (loss)	1,559	1,040	4,427	3,190
Depreciation, depletion and amortization	1,985	2,265	5,947	6,797
Capital expenditures	$ 53	$ 258	$ 255	$ 437