Investment Securities (Additional Information) (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2016
Schedule of Available-for-sale Securities [Line Items]
Trading account securities	$ 5,819,000	$ 5,819,000		$ 5,819,000		$ 9,255,000
Net gain (loss) on trading account securities		184,000	$ 285,000	113,000	$ 713,000
Investments, Fair Value Disclosure	126,000	126,000		126,000
Unrealized Loss on Securities	$ 19,000
Gain (Loss) on Sale of Securities, Net		$ 96,000		$ 660,000
Two Privately Issued Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities in loss position, depreciation percentage	12.92%	12.92%		12.92%
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale debt securities in loss position, depreciation percentage	98.88%	98.88%		98.88%
Debt Securities [Member] | Downgraded Due To Potential Credit Losses [Member]
Schedule of Available-for-sale Securities [Line Items]
Carrying Value Of Downgraded Due To Potential Credit Losses	$ 1,800,000	$ 1,800,000		$ 1,800,000
Debt Securities [Member] | Downgraded Privately Issued CMOs [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Market Value Of Downgraded Privately Issued Collateralized Mortgage Obligations	$ 2,500,000	$ 2,500,000		$ 2,500,000