Deposits - Interest expense on deposits (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Interest expense on deposits
Passbook Savings	$ 5	$ 7
Money Market Accounts	1
Certificates of Deposit	741	1,004
Interest expense on deposits	$ 747	$ 1,011

Aggregate amount of interest expense on all deposits.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.6)
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

+ Details

Name:	us-gaap_InterestExpenseDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of interest expense on domestic certificates of deposit liabilities.

+ References

+ Details

Name:	us-gaap_InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of interest expense on domestic money market demand account deposit liabilities.

+ References

+ Details

Name:	us-gaap_InterestExpenseDomesticDepositLiabilitiesMoneyMarket
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of interest expense on domestic savings deposit liabilities.

+ References

+ Details

Name:	us-gaap_InterestExpenseDomesticDepositLiabilitiesSavings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_InterestExpenseOnDepositLiabilitiesDisclosuresAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration