Loans, Allowance for Loan Losses and Impaired Loans (Details 5) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Mar. 31, 2017	Sep. 30, 2016
Bank impaired loans
With no related allowance recorded, Recorded investment	$ 6,673	$ 7,957
With an allowance recorded, Recorded investment	2,170	2,412
Recorded investment, Total	8,843	10,369
With no related allowance recorded, unpaid principal balance	6,673	7,957
With an allowance recorded, unpaid principal balance	2,170	2,412
Unpaid principal balance, Total	8,843	10,369
With an allowance recorded, Related allowance	465	606
With no related allowance recorded, Average recorded investment	7,316	8,171
With an allowance recorded, Average recorded investment	2,291	2,183
Average recorded investment, Total	9,607	10,354
With no related allowance recorded, Interest income recognized	53	237
With an allowance recorded, Interest income recognized	16	61
Interest income recognized, Total	69	298
Residential Real Estate
Bank impaired loans
With no related allowance recorded, Recorded investment	2,976	3,807
With an allowance recorded, Recorded investment	1,755	1,891
Recorded investment, Total	4,731	5,698
With no related allowance recorded, unpaid principal balance	2,976	3,807
With an allowance recorded, unpaid principal balance	1,755	1,891
Unpaid principal balance, Total	4,731	5,698
With an allowance recorded, Related allowance	359	503
With no related allowance recorded, Average recorded investment	3,392	3,817
With an allowance recorded, Average recorded investment	1,823	1,808
Average recorded investment, Total	5,215	5,625
With no related allowance recorded, Interest income recognized	21	132
With an allowance recorded, Interest income recognized	16	50
Interest income recognized, Total	37	182
Commercial/Agriculture Real Estate
Bank impaired loans
With no related allowance recorded, Recorded investment	1,832	2,326
With an allowance recorded, Recorded investment	0	0
Recorded investment, Total	1,832	2,326
With no related allowance recorded, unpaid principal balance	1,832	2,326
With an allowance recorded, unpaid principal balance	0	0
Unpaid principal balance, Total	1,832	2,326
With an allowance recorded, Related allowance	0	0
With no related allowance recorded, Average recorded investment	2,079	2,326
With an allowance recorded, Average recorded investment	0	0
Average recorded investment, Total	2,079	2,326
With no related allowance recorded, Interest income recognized	0	27
With an allowance recorded, Interest income recognized	0	0
Interest income recognized, Total	0	27
Consumer Non-real Estate
Bank impaired loans
With no related allowance recorded, Recorded investment	357	247
With an allowance recorded, Recorded investment	278	342
Recorded investment, Total	635	589
With no related allowance recorded, unpaid principal balance	357	247
With an allowance recorded, unpaid principal balance	278	342
Unpaid principal balance, Total	635	589
With an allowance recorded, Related allowance	59	76
With no related allowance recorded, Average recorded investment	302	451
With an allowance recorded, Average recorded investment	310	339
Average recorded investment, Total	612	790
With no related allowance recorded, Interest income recognized	10	36
With an allowance recorded, Interest income recognized	0	10
Interest income recognized, Total	10	46
Commercial/Agricultural Non-real Estate
Bank impaired loans
With no related allowance recorded, Recorded investment	1,508	1,577
With an allowance recorded, Recorded investment	137	179
Recorded investment, Total	1,645	1,756
With no related allowance recorded, unpaid principal balance	1,508	1,577
With an allowance recorded, unpaid principal balance	137	179
Unpaid principal balance, Total	1,645	1,756
With an allowance recorded, Related allowance	47	27
With no related allowance recorded, Average recorded investment	1,543	1,577
With an allowance recorded, Average recorded investment	158	36
Average recorded investment, Total	1,701	1,613
With no related allowance recorded, Interest income recognized	22	42
With an allowance recorded, Interest income recognized	0	1
Interest income recognized, Total	$ 22	$ 43