Quarterly Financial Data (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Summary of the unaudited quarterly results
Total revenue	$ 13,843	$ 13,959	$ 12,210	$ 11,916	$ 13,901	$ 12,999	$ 13,334	$ 12,522	$ 51,928	$ 52,756	$ 54,488
Operating income from continuing operations	4,638	4,793	3,689	3,222	2,933	4,257	4,212	4,121	16,342	15,523	11,991
Income from continuing operations	2,854	3,174	1,946	2,155	2,190	3,051	2,824	2,860	10,129	10,925	405
Income (loss) from discontinued operations	(114)	(112)	(223)	551	(20,855)	791	(336)	(9,031)	102	(29,431)	(21,494)
Net income (loss)	$ 2,740	$ 3,062	$ 1,723	$ 2,706	$ (18,665)	$ 3,842	$ 2,488	$ (6,171)	$ 10,231	$ (18,506)	$ (21,089)
Basic income (loss) per share:
Continuing operations	$ 0.17	$ 0.18	$ 0.11	$ 0.12	$ 0.13	$ 0.17	$ 0.16	$ 0.16	$ 0.58	$ 0.63	$ 0.02
Discontinued operations	$ (0.01)	$ (0.01)	$ (0.01)	$ 0.03	$ (1.20)	$ 0.05	$ (0.02)	$ (0.52)	$ 0.01	$ (1.69)	$ (1.24)
Net income (loss)	$ 0.16	$ 0.17	$ 0.10	$ 0.15	$ (1.07)	$ 0.22	$ 0.14	$ (0.36)	$ 0.59	$ (1.06)	$ (1.21)
Diluted income (loss) per share:
Continuing operations	$ 0.17	$ 0.18	$ 0.11	$ 0.12	$ 0.13	$ 0.17	$ 0.16	$ 0.16	$ 0.58	$ 0.63	$ 0.02
Discontinued operations	$ (0.01)	$ (0.01)	$ (0.01)	$ 0.03	$ (1.19)	$ 0.05	$ (0.02)	$ (0.52)	$ 0.01	$ (1.69)	$ (1.24)
Net (loss) income	$ 0.16	$ 0.17	$ 0.10	$ 0.15	$ (1.07)	$ 0.22	$ 0.14	$ (0.35)	$ 0.59	$ (1.06)	$ (1.21)