Selected Quarterly Financial Data (unaudited): Selected financial data (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Quarterly Financial Information Disclosure [Abstract]
Interest and dividend income	$ 7,521	$ 7,575	$ 7,552	$ 7,589	$ 7,750	$ 8,019	$ 7,804	$ 8,032
Interest expense	(1,052)	(1,076)	(1,111)	(1,200)	(1,294)	(1,391)	(1,531)	(1,731)	(4,439)	(5,947)	(8,533)
Net interest income	6,469	6,499	6,441	6,389	6,456	6,628	6,273	6,301	25,798	25,658	25,433
Provision for loan losses	(165)	(1,385)	(1,175)	(200)	(900)	(900)	(1,050)	(650)	(2,925)	(3,500)	(6,758)
Non-interest income	2,397	2,372	2,778	2,715	2,503	2,341	2,493	2,444	10,262	9,781	8,681
Non-interest expense	(7,066)	(6,237)	(6,184)	(6,377)	(6,678)	(6,097)	(6,572)	(6,221)	(25,864)	(25,568)	(25,963)
Income before income taxes	1,635	1,249	1,860	2,527	1,381	1,972	1,144	1,874
Provision for federal income taxes	740	373	582	819	230	624	336	591	2,514	1,781	304
Net income	895	876	1,278	1,708	1,151	1,348	808	1,283	4,757	4,590	1,089
Preferred stock dividends	(151)	(151)	(207)	(201)	(208)	(208)	(208)	(208)	(710)	(832)	(832)
Preferred stock accretion	(47)	(47)	(126)	(63)	(61)	(61)	(59)	(59)	(283)	(240)	(225)
Repurchase of preferred stock at a discount	0	0	255	0					255	0	0
Net income to common shareholders	$ 697	$ 678	$ 1,200	$ 1,444	$ 882	$ 1,079	$ 541	$ 1,016	$ 4,019	$ 3,518	$ 32
Net income per common share
Basic (in dollars per share)	$ 0.10	$ 0.10	$ 0.18	$ 0.21	$ 0.13	$ 0.16	$ 0.08	$ 0.15	$ 0.59	$ 0.52	$ 0.00
Diluted (in dollars per share)	$ 0.10	$ 0.10	$ 0.17	$ 0.21	$ 0.13	$ 0.16	$ 0.08	$ 0.15	$ 0.58	$ 0.52	$ 0.00