Loans and Allowance for Loan Losses (Troubled Debt Restructurings) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
	Mar. 31, 2014 Number	Mar. 31, 2015 Number	Mar. 31, 2014 Number
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Number of Loans	1	2	4
Pre- Modification Principal Balance	$ 42	$ 165	$ 855
Post- Modification Principal Balance	42	172	883
Residential real estate
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Number of Loans	1	2	3
Pre- Modification Principal Balance	42	165	139
Post- Modification Principal Balance	42	172	159
Commercial real estate
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Number of Loans			1
Pre- Modification Principal Balance			716
Post- Modification Principal Balance			$ 724