Fair Value Disclosures - Carrying amount and estimated fair value (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financial assets:
Investment securities available-for-sale, at fair value	$ 36,078	$ 36,975
Securities held-to-maturity	1,075	1,150
Carrying Value
Financial assets:
Cash and cash equivalents	23,667	20,997
Interest-bearing time deposits in banks	650	650
Investment securities available-for-sale, at fair value	36,078	36,975
Securities held-to-maturity	1,064	1,128
Equity securities	338	350
Loans receivable	274,485	278,120
FHLB stock	1,335	1,450
Accrued interest receivable	1,274	1,249
Financial liabilities:
Deposits	314,911	312,049
Long-term borrowings	15,978	17,760
Accrued interest payable	40	35
Fair Value
Financial assets:
Cash and cash equivalents	23,667	20,997
Interest-bearing time deposits in banks	650	650
Investment securities available-for-sale, at fair value	36,078	36,975
Securities held-to-maturity	1,075	1,150
Equity securities	338	350
Loans receivable	278,475	281,502
FHLB stock	1,335	1,450
Accrued interest receivable	1,274	1,249
Financial liabilities:
Deposits	310,821	313,970
Long-term borrowings	19,355	21,985
Accrued interest payable	40	35
Level 1
Financial assets:
Cash and cash equivalents	23,667	20,997
Equity securities	338	350
Accrued interest receivable	1,274	1,249
Financial liabilities:
Deposits	91,989	94,709
Accrued interest payable	40	35
Level 2
Financial assets:
Interest-bearing time deposits in banks	650	650
Investment securities available-for-sale, at fair value	33,573	33,965
Securities held-to-maturity	1,075	1,150
FHLB stock	1,335	1,450
Financial liabilities:
Long-term borrowings	19,355	21,985
Level 3
Financial assets:
Investment securities available-for-sale, at fair value	2,505	3,010
Loans receivable	278,475	281,502
Financial liabilities:
Deposits	$ 218,832	$ 219,261