Loans Receivable, Net and Allowance for Loan Losses - Schedule of Loans Evaluated for Impairment (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Sep. 30, 2012	Jun. 30, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 950,978	$ 957,311	$ 950,978
Individually evaluated for impairment	30,382	25,971
Loans acquired with deteriorated credit quality	7,104	7,500
Collectively evaluated for impairment	913,492	923,840
Residential Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	688,724	696,350	688,724
Individually evaluated for impairment	12,953	7,942
Loans acquired with deteriorated credit quality	335	271
Collectively evaluated for impairment	675,436	688,137
Construction Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	5,097	3,805	5,097
Individually evaluated for impairment
Loans acquired with deteriorated credit quality
Collectively evaluated for impairment	5,097	3,805
Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	164,186	160,192	164,186
Individually evaluated for impairment	16,612	17,415
Loans acquired with deteriorated credit quality	6,240	6,159
Collectively evaluated for impairment	141,334	136,618
Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	11,111	12,818	11,111
Individually evaluated for impairment	383	423
Loans acquired with deteriorated credit quality	514	1,007
Collectively evaluated for impairment	10,214	11,388
Obligations of States and Political Subdivisions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	36,147	33,736	36,147
Individually evaluated for impairment
Loans acquired with deteriorated credit quality
Collectively evaluated for impairment	36,147	33,736
Home Equity Loans and Lines of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	43,402	47,925	43,402
Individually evaluated for impairment	434	191
Loans acquired with deteriorated credit quality	15	44
Collectively evaluated for impairment	42,953	47,690
Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	2,311	2,485	2,311
Individually evaluated for impairment
Loans acquired with deteriorated credit quality		19
Collectively evaluated for impairment	$ 2,311	$ 2,466