Business Segments - Business segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Sep. 30, 2012	Sep. 30, 2011
Revenues	$ 35,708	$ 33,030	$ 102,633	$ 94,715
Operating profit	6,070	4,891	14,786	11,549
Corporate expenses	(1,050)	(899)	(3,740)	(3,359)
Interest expense	1,137	537	2,145	2,135
Capital expenditures	14,016	16,106	26,948	23,305
Depreciation, depletion and amortization	3,624	3,196	10,362	9,502
Cash items	742	11,838	742	11,838	6,713	21,026
Total identifiable assets	283,517		283,517		275,705
(a) Receivable on previously capitalized real estate taxes on Anacostia property			0	2,250
Transportation
Revenues	28,794	26,907	82,609	77,197
Operating profit	3,513	2,682	8,109	6,706
Corporate expenses	(406)	(396)	(1,284)	(1,187)
Capital expenditures	3,311	1,202	10,672	6,605
Depreciation, depletion and amortization	1,865	1,690	5,445	5,018
Identifiable assets	46,690		46,690		42,642
Mining royalty land
Revenues	1,299	1,101	3,874	3,103
Operating profit	1,156	958	3,457	2,671
Corporate expenses	(176)	(164)	(528)	(491)
Interest expense	15	10	38	29
Capital expenditures	0	11,039	0	11,039
Depreciation, depletion and amortization	27	27	75	86
Identifiable assets	39,492		39,492		39,695
Developed property rentals
Revenues	5,615	5,022	16,150	14,415
Operating profit	2,451	2,150	6,960	5,531
Corporate expenses	(264)	(245)	(792)	(736)
Interest expense	1,122	527	2,107	2,106
Capital expenditures	9,978	2,916	13,816	5,573
Capital expenditures - Capitalized interest	367	533	1,375	1,111
Capital expenditures - Internal labor	106	173	324	431
Capital expenditures - Real estate taxes (a)	254	243	761	(1,454)
Depreciation, depletion and amortization	1,629	1,382	4,532	4,096
Identifiable assets	194,744		194,744		184,358
(a) Receivable on previously capitalized real estate taxes on Anacostia property
Corporate
Corporate expenses	(204)	(94)	(1,136)	(945)
Depreciation, depletion and amortization	103	97	310	302
Identifiable assets	$ 1,849		$ 1,849		$ 2,297