LOANS AND ALLOWANCE FOR CREDIT LOSSES - Additional information (Details)	3 Months Ended	6 Months Ended		12 Months Ended
	Sep. 30, 2023 USD ($) loan	Sep. 30, 2023 USD ($) loan	Sep. 30, 2022 USD ($)	Mar. 31, 2023 USD ($) loan	Jun. 30, 2023 USD ($)	Apr. 01, 2023 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred loan fees	$ 4,400,000	$ 4,400,000		$ 4,400,000
Discount On Loans Receivable	1,300,000	1,300,000		1,400,000
Premiums On Loans Receivable.	2,000,000.0	2,000,000.0		$ 2,100,000
Loans Pledged as Collateral	1,000,279,000	$ 1,000,279,000
Percentage Of Loans And Extensions Of Credit Outstanding		15.00%
Number of loans to one borrower over regulatory limit | loan		0		0
Allowance for credit losses (in dollars)	15,346,000	$ 15,346,000		$ 15,309,000	$ 15,343,000
Non-accrual loans with no ACL	159,000	159,000
Non-accrual loans with ACL	39,000	39,000
Non-accruals, Allowance	1,000	1,000
Interest income foregone on non-accrual loans		5,000	$ 7,000	14,000
Total loans	$ 1,015,625,000	$ 1,015,625,000
Number of loan modifications approved | loan	0	0
Percentage of delinquent loan amount		75.00%
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts			0
30 To 89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 1,234,000	$ 1,234,000
ASU 2016-13
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number Of impaired loans on nonaccrual status | loan						2
Adjustment | ASU 2016-13
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses (in dollars)				42,000		$ 42,000
Fully Guaranteed SBA Or USDA Loans | 30 To 89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	130,000	130,000
Asset Pledged as Collateral | FHLB and FRB Borrowing Arrangements
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Pledged as Collateral	578,100,000	578,100,000
Asset Pledged as Collateral | Financing receivable | Commercial Business
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Pledged as Collateral	69,000	69,000
Asset Pledged as Collateral | Financing receivable | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Pledged as Collateral	90,000	90,000
Commercial Real Estate Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	917,432,000	917,432,000
Commercial Real Estate Portfolio Segment | Commercial Business
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses (in dollars)	5,339,000	5,339,000		3,123,000	5,215,000
Total loans	242,041,000	242,041,000
Commercial Real Estate Portfolio Segment | Commercial Business | 30 To 89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	966,000	966,000
Commercial Real Estate Portfolio Segment | Commercial Business | Adjustment | ASU 2016-13
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses (in dollars)				1,884,000
Commercial Real Estate Portfolio Segment | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses (in dollars)	7,138,000	7,138,000		8,894,000	7,205,000
Total loans	561,377,000	561,377,000
Commercial Real Estate Portfolio Segment | Commercial Real Estate | 30 To 89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	268,000	268,000
Commercial Real Estate Portfolio Segment | Commercial Real Estate | Adjustment | ASU 2016-13
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses (in dollars)				(1,494,000)
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses (in dollars)	1,604,000	1,604,000		1,127,000	$ 1,677,000
Total loans	98,193,000	98,193,000
Consumer | Adjustment | ASU 2016-13
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses (in dollars)				$ 483,000
Consumer | Real estate one-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 96,351,000	$ 96,351,000