Loans and Allowance for Loan Losses (Additional Information) (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable Unpaid Principal Balance	$ 11,116,000		$ 11,116,000		$ 11,726,000
Mortgage Loans in Process of Foreclosure, Amount	1,200,000		1,200,000		837,000
Loan Servicing Rights [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable Unpaid Principal Balance	45,100,000	$ 10,700,000	45,100,000	$ 10,700,000	$ 13,600,000
Bank Servicing Fees	1,000	35,000	45,000	62,000
Financial Services Costs	$ 41,000	$ 34,000	$ 110,000	$ 69,000