Loans Receivable - Schedule of Loans Evaluated for Impairment (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 1,699,050	$ 1,454,311
Individually Evaluated for Impairment	9,735	14,502
Collectively Evaluated for Impairment	1,689,315	1,439,809
Obligations of States and Political Subdivisions [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	48,118	40,416
Collectively Evaluated for Impairment	48,118	40,416
Home Equity Loans and Lines of Credit [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	48,212	43,170
Individually Evaluated for Impairment	27	36
Collectively Evaluated for Impairment	48,185	43,134
Auto Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	523	3,611
Individually Evaluated for Impairment		16
Collectively Evaluated for Impairment	523	3,595
Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,002	1,716
Individually Evaluated for Impairment	3	6
Collectively Evaluated for Impairment	1,999	1,710
Residential [Member] \| Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	713,326	623,375
Individually Evaluated for Impairment	1,393	1,342
Collectively Evaluated for Impairment	711,933	622,033
Construction [Member] \| Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	16,768	25,024
Collectively Evaluated for Impairment	16,768	25,024
Commercial [Member] \| Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	821,958	678,841
Individually Evaluated for Impairment	7,664	12,165
Collectively Evaluated for Impairment	814,294	666,676
Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	48,143	38,158
Individually Evaluated for Impairment	648	937
Collectively Evaluated for Impairment	$ 47,495	$ 37,221

The balance of financing receivables that were collectively evaluated for impairment.

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The balance of financing receivables that were individually evaluated for impairment.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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