Business Segments - Business segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Sep. 30, 2015
Segment Reporting Information [Line Items]
Revenues	$ 9,243	$ 8,497	$ 27,681	$ 25,747
Operating profit	1,966	3,889	12,075	8,393
Corporate expenses unallocated to discontinued operations	0	0	0	(1,081)
Interest expense	392	459	1,288	1,524
Depreciation, depletion and amortization			6,068	5,663
Cash items	3,469		3,469		$ 419
Total identifiable net assets	255,582		255,582		252,478
Asset Management
Segment Reporting Information [Line Items]
Revenues	6,927	6,509	21,416	20,596
Operating profit before corporate expenses	3,318	3,289	10,129	9,862
Corporate expenses	(354)	(210)	(1,252)	(1,007)
Interest expense	392	459	1,288	1,524
Capital expenditures	699	231	10,340	1,498
Depreciation, depletion and amortization	1,985	1,694	5,618	5,256
Total identifiable net assets	161,487		161,487		151,023
Mining royalty lands
Segment Reporting Information [Line Items]
Revenues	2,059	1,735	5,496	4,414
Operating profit before corporate expenses	1,940	1,576	5,114	3,967
Corporate expenses	(52)	(223)	(182)	(1,067)
Capital expenditures	101	0	106	0
Depreciation, depletion and amortization	15	39	80	100
Total identifiable net assets	39,737		39,737		39,300
Land Development and Construction
Segment Reporting Information [Line Items]
Revenues	257	253	769	737
Operating profit before corporate expenses	(2,608)	(419)	(744)	(1,686)
Corporate expenses	(278)	(124)	(990)	(595)
Capital expenditures	673	1,033	2,523	2,195
Depreciation, depletion and amortization	66	72	193	210
Total identifiable net assets	50,357		50,357		60,682
Corporate
Segment Reporting Information [Line Items]
Total identifiable net assets	532		532		$ 1,054
Total Segments
Segment Reporting Information [Line Items]
Revenues	9,243	8,497	27,681	25,747
Operating profit	1,966	3,889	12,075	8,393
Corporate expenses	(684)	(557)	(2,424)	(3,750)
Corporate expenses unallocated to discontinued operations	0	0	0	(1,081)
Capital expenditures	1,473	1,264	12,969	3,693
Depreciation, depletion and amortization	$ 2,066	$ 1,805	$ 5,726	$ 5,566