Investment Securities - Gross Unrealized Loss (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Schedule of available-for-sale securities and cost-method investments [Line Items]
Total investment securities in an unrealized loss position less than 12 months fair value	$ 46,718	$ 15,287
Total investment securities in an unrealized loss position less than 12 months gross unrealized loss	(2,655)	(35)
Total investment securities in an unrealized loss position 12 months or more fair value	2,381	3,848
Total investment securities in an unrealized loss position 12 months or more gross unrealized loss	(119)	(152)
Total investment securities in an unrealized loss position fair value	49,099	19,135
Total investment securities in an unrealized loss position gross unrealized loss	(2,774)	(187)
U. S. Government Agencies [Member]
Schedule of available-for-sale securities and cost-method investments [Line Items]
Less than 12 Months: Fair Value	4,442	4,993
Less than 12 Months: Unrealized Losses	(558)	(7)
Total: Fair Value	4,442	4,993
Total: Unrealized Losses	(558)	(7)
State And Municipal Obligations [Member]
Schedule of available-for-sale securities and cost-method investments [Line Items]
Less than 12 Months: Fair Value	9,951	1,819
Less than 12 Months: Unrealized Losses	(935)	(3)
Total: Fair Value	9,951	1,819
Total: Unrealized Losses	(935)	(3)
Single Issuer Trust Preferred Security [Member]
Schedule of available-for-sale securities and cost-method investments [Line Items]
12 Months or longer: Fair Value	922	875
12 Months or longer: Unrealized Losses	(78)	(125)
Total: Fair Value	922	875
Total: Unrealized Losses	(78)	(125)
Corporate Debt Securities [Member]
Schedule of available-for-sale securities and cost-method investments [Line Items]
Less than 12 Months: Fair Value	28,408	8,475
Less than 12 Months: Unrealized Losses	(1,092)	(25)
12 Months or longer: Fair Value	1,459	2,973
12 Months or longer: Unrealized Losses	(41)	(27)
Total: Fair Value	29,867	11,448
Total: Unrealized Losses	(1,133)	$ (52)
MBS Securities {Member}
Schedule of available-for-sale securities and cost-method investments [Line Items]
Less than 12 Months: Fair Value	2,438
Less than 12 Months: Unrealized Losses	(66)
Total: Fair Value	2,438
Total: Unrealized Losses	(66)
U.S. Treasury Note [Member]
Schedule of available-for-sale securities and cost-method investments [Line Items]
Less than 12 Months: Fair Value	1,479
Less than 12 Months: Unrealized Losses	(4)
Total: Fair Value	1,479
Total: Unrealized Losses	$ (4)