Business Segments - Business segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenues	$ 33,057	$ 30,359
Operating profit	4,408	3,214
Corporate expenses	(1,174)	(1,096)
Interest expense	428	804
Capital expenditures (b)	10,951	5,335
Depreciation, depletion and amortization	3,271	3,083
Cash items	1,440	19,050	6,713	21,026
Total identifiable assets	276,694		275,705
(a) Receivable on previously capitalized real estate taxes on Anacostia property	31	2,043
Transportation
Revenues	26,639	24,841
Operating profit	2,268	1,838
Corporate expenses	(471)	(395)
Capital expenditures (b)	6,787	4,789
Depreciation, depletion and amortization	1,753	1,608
Identifiable assets	47,293		42,642
Mining royalty land
Revenues	1,331	977
Operating profit	1,199	848
Corporate expenses	(176)	(164)
Interest expense	11	10
Capital expenditures (b)	0	0
Depreciation, depletion and amortization	25	32
Identifiable assets	39,436		39,695
Developed property rentals
Revenues	5,087	4,541
Operating profit	2,115	1,624
Corporate expenses	(264)	(245)
Interest expense	417	794
Capital expenditures (b)	3,212	1,718
Capital expenditures - Capitalized interest	591	294
Capital expenditures - Internal labor	110	141
Capital expenditures - Real estate taxes (a)	251	(1,607)
Depreciation, depletion and amortization	1,388	1,341
Identifiable assets	186,692		184,358
(a) Receivable on previously capitalized real estate taxes on Anacostia property
Corporate
Corporate expenses	(263)	(292)
Depreciation, depletion and amortization	105	102
Identifiable assets	$ 1,833		$ 2,297