Company’s business segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Revenues	$ 41,506	$ 37,481	$ 31,220
Operating profit before corporate expenses	15,702	11,658	5,345
Corporate expenses	(4,002)	(3,662)	(3,071)
Operating profit	11,700	7,996	2,274
Interest expense	4,315	3,045	2,304
Depreciation, depletion and amortization	10,975	11,462	12,946
Capital expenditures	11,217	27,615	16,530
Industrial Commercial [Member]
Segment Reporting Information [Line Items]
Revenues	5,354	3,681	2,575
Operating profit before corporate expenses	2,551	1,592	612
Corporate expenses	(787)	(632)	(843)
Depreciation, depletion and amortization	1,374	907	578
Capital expenditures	664	1,284	852
Mining Properties [Member]
Segment Reporting Information [Line Items]
Revenues	12,527	10,683	9,465
Operating profit before corporate expenses	11,009	9,305	8,558
Corporate expenses	(449)	(414)	(318)
Depreciation, depletion and amortization	497	586	199
Capital expenditures	2	11,218	522
Development [Member]
Segment Reporting Information [Line Items]
Revenues	1,801	1,674	1,563
Operating profit before corporate expenses	(1,954)	(2,791)	(2,548)
Corporate expenses	(2,387)	(2,284)	(1,557)
Depreciation, depletion and amortization	182	189	208
Capital expenditures	9,990	14,521	14,242
Multifamily Segment [Member]
Segment Reporting Information [Line Items]
Revenues	21,824	21,443	17,617
Operating profit before corporate expenses	4,096	3,552	(1,277)
Corporate expenses	(379)	(332)	(353)
Depreciation, depletion and amortization	8,768	9,535	11,752
Capital expenditures	561	592	914
Total Segments [Member]
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	$ 10,821	$ 11,217	$ 12,737