Loans and Allowance for Credit Losses on Loans, Loan Segments and Classes Prior to Adoption of ASU 2016-13 (CECL) (Details) - USD ($)		Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022
Major Loan Segments and Classes [Abstract]
Total gross loans	[1]			$ 1,408,791,000
Allowance for loan losses		$ (20,309,000)	$ (20,249,000)	(21,212,000)	$ (22,289,000)	$ (22,147,000)	$ (22,761,000)
Deferred fees and cost, net				75,000
Net loans receivable		1,436,866,000		1,387,654,000
Accrued interest receivable		6,400,000		5,500
Residential Real Estate [Member] | Residential Real Estate [Member]
Major Loan Segments and Classes [Abstract]
Total gross loans				372,443,000
Allowance for loan losses		(4,010,000)	(3,869,000)	(2,794,000)	(2,492,000)	(2,471,000)
Residential Real Estate [Member] | Construction and Land [Member]
Major Loan Segments and Classes [Abstract]
Total gross loans				19,072,000
Allowance for loan losses					(193,000)	(177,000)	(141,000)
Residential Real Estate [Member] | Multi-family [Member]
Major Loan Segments and Classes [Abstract]
Total gross loans				66,496,000
Allowance for loan losses					(167,000)	(159,000)	(119,000)
Residential Real Estate [Member] | Real Estate [Member]
Major Loan Segments and Classes [Abstract]
Allowance for loan losses					(2,492,000)		(2,373,000)
Commercial Real Estate [Member] | Real Estate [Member]
Major Loan Segments and Classes [Abstract]
Total gross loans				693,436,000
Allowance for loan losses		(12,523,000)	(12,356,000)	(14,839,000)	(15,450,000)	(15,392,000)	(16,221,000)
Commercial Real Estate [Member] | Construction [Member]
Major Loan Segments and Classes [Abstract]
Total gross loans				121,958,000
Allowance for loan losses					(1,100,000)	(1,044,000)	(1,114,000)
Consumer Loan [Member]
Major Loan Segments and Classes [Abstract]
Total gross loans				108,022,000
Consumer Loan [Member] | Home Equity [Member]
Major Loan Segments and Classes [Abstract]
Total gross loans				22,752,000
Allowance for loan losses		(192,000)	(188,000)	(46,000)	(38,000)	(44,000)	(89,000)
Consumer Loan [Member] | Consumer [Member]
Major Loan Segments and Classes [Abstract]
Total gross loans				4,612,000
Allowance for loan losses		(486,000)	(490,000)	(332,000)	(284,000)	(274,000)	(349,000)
Commercial Loans [Member]
Major Loan Segments and Classes [Abstract]
Total gross loans				108,022,000
Allowance for loan losses		$ (3,098,000)	$ (3,346,000)	$ (3,201,000)	$ (2,565,000)	$ (2,586,000)	$ (2,355,000)

[1] Loan balances exclude accrued interest receivable of $5.5 million at June 30, 2023, which is included in accrued interest receivable in the consolidated statement of financial condition.