Loans, Allowance for Credit Losses and Credit Quality - Schedule of Information Regarding Nonaccrual Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2024		Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	[1]	Jun. 30, 2023	Dec. 31, 2022
Accounts Notes And Loans Receivable [Line Items]
With an Allowance for Credit Losses	$ 9,068	[1]	$ 9,025	$ 8,591	$ 8,292		$ 8,470	$ 7,200
Total	1,098			1,213
Nonperforming Financing Instruments
Accounts Notes And Loans Receivable [Line Items]
With an Allowance for Credit Losses	0			0
Without an Allowance for Credit Losses	1,098			1,213
Total	1,098			1,213
Real Estate Loans | Home Equity Lines of Credit and Loans
Accounts Notes And Loans Receivable [Line Items]
With an Allowance for Credit Losses	382	[1]	363	321	207		203	194
Total	85			22
Real Estate Loans | Home Equity Lines of Credit and Loans | Nonperforming Financing Instruments
Accounts Notes And Loans Receivable [Line Items]
With an Allowance for Credit Losses	0			0
Without an Allowance for Credit Losses	85			22
Total	85			22
Real Estate Loans | One- to Four-Family Residential
Accounts Notes And Loans Receivable [Line Items]
With an Allowance for Credit Losses	3,685	[1]	$ 3,604	3,555	$ 2,020		$ 1,980	$ 1,703
Total	1,012			1,191
Real Estate Loans | One- to Four-Family Residential | Nonperforming Financing Instruments
Accounts Notes And Loans Receivable [Line Items]
With an Allowance for Credit Losses	0			0
Without an Allowance for Credit Losses	1,012			1,191
Total	1,012			$ 1,191
Real Estate Loans | Consumer | Nonperforming Financing Instruments
Accounts Notes And Loans Receivable [Line Items]
With an Allowance for Credit Losses	0
Without an Allowance for Credit Losses	1
Total	$ 1

[1] (1) Balances of accrued interest receivable excluded from amortized cost and the calculation of allowance for credit losses amounted to $3.5 million and $2.9 million as of September 30, 2024 and September 30, 2023.