Summary of Significant Accounting Policies - Recently Issued Accounting Standards (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023	Oct. 01, 2023	Sep. 30, 2023
Significant Accounting Policies
Allowance for credit losses for unfunded commitments	$ 31,000	$ 31,000
Retained earnings	28,094,000			$ 28,242,000
Allowance for credit loss related to the available for sale portfolio	0
Accrued interest receivable on available for sale debt securities	277,000
Accrued interest receivable related to loans	$ 376,000
Cumulative Effect, Period of Adoption, Adjustment | ASU 2016-13
Significant Accounting Policies
Allowance for credit losses for unfunded commitments			$ 29,000
Retained earnings			$ 368,000