Loans and Allowance for Credit Losses on Loans, Major Loan Segments and Classes (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	$ 1,457,175,000	[1],[2]		$ 1,408,866,000
Allowance for credit losses on loans	(20,309,000)		$ (20,249,000)	(21,212,000)	$ (22,289,000)	$ (22,147,000)	$ (22,761,000)
Net loans receivable	1,436,866,000			1,387,654,000
Deferred fees and cost, net	54,000
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	401,656,000
Allowance for credit losses on loans	(4,010,000)		(3,869,000)	(2,794,000)	(2,492,000)	(2,471,000)
Residential Real Estate [Member] | Real Estate [Member]
Major Loan Segments and Classes [Abstract]
Allowance for credit losses on loans					(2,492,000)		(2,373,000)
Commercial Real Estate [Member] | Real Estate [Member]
Major Loan Segments and Classes [Abstract]
Total gross loans	911,731,000
Allowance for credit losses on loans	(12,523,000)		(12,356,000)	(14,839,000)	(15,450,000)	(15,392,000)	(16,221,000)
Consumer Loan [Member] | Home Equity [Member]
Major Loan Segments and Classes [Abstract]
Total gross loans	26,167,000
Allowance for credit losses on loans	(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	4,691,000
Allowance for credit losses on loans	(486,000)		(490,000)	(332,000)	(284,000)	(274,000)	(349,000)
Commercial Loans [Member]
Major Loan Segments and Classes [Abstract]
Total gross loans	112,930,000
Allowance for credit losses on loans	$ (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 $6.4 million at December 31, 2023, which is included in accrued interest receivable in the consolidated statement of financial condition.

[2] Loan balances include net deferred fees/cost of $54,000 at December 31, 2023.