Deposits - Interest expense on deposits (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Interest expense on deposits
Passbook Savings	$ 6	$ 6
Money Market Accounts		1
Certificates of Deposit	1,255	921
Interest expense on deposits	$ 1,261	$ 928

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=114873765&loc=SL114874048-224260

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Amount of interest expense on domestic certificates of deposit liabilities.

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- Definition

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

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- Definition

Amount of interest expense on domestic savings deposit liabilities.

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