Loans and Allowance for Credit Losses on Loans, Nonaccrual Loans (Details)		3 Months Ended
		Sep. 30, 2023 USD ($) Loan		Jun. 30, 2023 USD ($) Loan
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		$ 1,448,340,000	[1],[2]	$ 1,408,866,000
Total loans	[3]			1,408,791,000
Loans on non-accrual		5,474,000		5,458,000
Nonaccrual loans with recent history of delinquency greater than 90 days		2,900,000		3,100,000
Loan repayments		87,000,000
Loans returning to performing status		19,000
Charge-offs		3,000
Loans placed into nonperforming status		138,000
Accruing loans delinquent more than 90 days				0
Total Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		4,492,000
Total loans				3,202,000
30 to 59 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		93,000
Total loans				111,000
60 to 89 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		1,797,000
Total loans				740,000
90 Days or More Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		2,602,000
Total loans				2,351,000
Current [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		1,443,848,000
Total loans				1,405,589,000
Residential Real Estate [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Loans in the process of foreclosure		$ 637,000		$ 625,000
Number of loans in the process of foreclosure | Loan		3		3
Residential Real Estate [Member] | Residential Real Estate [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		$ 397,626,000
Total loans				$ 372,443,000
Loans on non-accrual		2,816,000		2,747,000
Residential Real Estate [Member] | Residential Real Estate [Member] | Total Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		2,202,000
Total loans				2,108,000
Residential Real Estate [Member] | Residential Real Estate [Member] | 30 to 59 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		19,000
Total loans				0
Residential Real Estate [Member] | Residential Real Estate [Member] | 60 to 89 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		306,000
Total loans				504,000
Residential Real Estate [Member] | Residential Real Estate [Member] | 90 Days or More Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		1,877,000
Total loans				1,604,000
Residential Real Estate [Member] | Residential Real Estate [Member] | Current [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		395,424,000
Total loans				370,335,000
Residential Real Estate [Member] | Construction and Land [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				19,072,000
Loans on non-accrual				0
Residential Real Estate [Member] | Construction and Land [Member] | Total Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				0
Residential Real Estate [Member] | Construction and Land [Member] | 30 to 59 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				0
Residential Real Estate [Member] | Construction and Land [Member] | 60 to 89 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				0
Residential Real Estate [Member] | Construction and Land [Member] | 90 Days or More Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				0
Residential Real Estate [Member] | Construction and Land [Member] | Current [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				19,072,000
Residential Real Estate [Member] | Multi-family [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				66,496,000
Loans on non-accrual				0
Residential Real Estate [Member] | Multi-family [Member] | Total Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				0
Residential Real Estate [Member] | Multi-family [Member] | 30 to 59 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				0
Residential Real Estate [Member] | Multi-family [Member] | 60 to 89 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				0
Residential Real Estate [Member] | Multi-family [Member] | 90 Days or More Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				0
Residential Real Estate [Member] | Multi-family [Member] | Current [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				66,496,000
Commercial Real Estate [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Loans in the process of foreclosure				$ 1,400
Number of loans in the process of foreclosure | Loan				2
Commercial Real Estate [Member] | Real Estate [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		910,165,000
Total loans				$ 693,436,000
Loans on non-accrual		1,307,000		1,318,000
Commercial Real Estate [Member] | Real Estate [Member] | Total Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		883,000
Total loans				887,000
Commercial Real Estate [Member] | Real Estate [Member] | 30 to 59 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		0
Total loans				0
Commercial Real Estate [Member] | Real Estate [Member] | 60 to 89 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		233,000
Total loans				235,000
Commercial Real Estate [Member] | Real Estate [Member] | 90 Days or More Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		650,000
Total loans				652,000
Commercial Real Estate [Member] | Real Estate [Member] | Current [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		909,282,000
Total loans				692,549,000
Commercial Real Estate [Member] | Construction [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				121,958,000
Loans on non-accrual				0
Commercial Real Estate [Member] | Construction [Member] | Total Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				0
Commercial Real Estate [Member] | Construction [Member] | 30 to 59 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				0
Commercial Real Estate [Member] | Construction [Member] | 60 to 89 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				0
Commercial Real Estate [Member] | Construction [Member] | 90 Days or More Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				0
Commercial Real Estate [Member] | Construction [Member] | Current [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans				121,958,000
Consumer Loan [Member] | Home Equity [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		25,467,000
Total loans				22,752,000
Loans on non-accrual		52,000		54,000
Consumer Loan [Member] | Home Equity [Member] | Total Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		56,000
Total loans				61,000
Consumer Loan [Member] | Home Equity [Member] | 30 to 59 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		43,000
Total loans				48,000
Consumer Loan [Member] | Home Equity [Member] | 60 to 89 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		0
Total loans				0
Consumer Loan [Member] | Home Equity [Member] | 90 Days or More Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		13,000
Total loans				13,000
Consumer Loan [Member] | Home Equity [Member] | Current [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		25,411,000
Total loans				22,691,000
Consumer Loan [Member] | Consumer [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		4,778,000
Total loans				4,612,000
Loans on non-accrual		43,000		63,000
Consumer Loan [Member] | Consumer [Member] | Total Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		95,000
Total loans				127,000
Consumer Loan [Member] | Consumer [Member] | 30 to 59 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		31,000
Total loans				63,000
Consumer Loan [Member] | Consumer [Member] | 60 to 89 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		21,000
Total loans				1,000
Consumer Loan [Member] | Consumer [Member] | 90 Days or More Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		43,000
Total loans				63,000
Consumer Loan [Member] | Consumer [Member] | Current [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		4,683,000
Total loans				4,485,000
Commercial Loans [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		110,304,000
Total loans				108,022,000
Loans on non-accrual		1,256,000		1,276,000
Commercial Loans [Member] | Total Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		1,256,000
Total loans				19,000
Commercial Loans [Member] | 30 to 59 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		0
Total loans				0
Commercial Loans [Member] | 60 to 89 Days Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		1,237,000
Total loans				0
Commercial Loans [Member] | 90 Days or More Past Due [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		19,000
Total loans				19,000
Commercial Loans [Member] | Current [Member]
Delinquent and/or Nonaccrual Loans by Past Due Status [Abstract]
Total loans		$ 109,048,000
Total loans				$ 108,003,000

[1] Loan balances exclude accrued interest receivable of $6.0 million at September 30, 2023, which is included in accrued interest receivable in the consolidated statement of financial condition.

[2] Loan balances include net deferred fees/cost of $62,000 at September 30, 2023.

[3] 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.