Financial Transactions with Off-Balance-Sheet Risk and Concentrations of Credit Risk - Schedule of Loan Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Concentration Risk [Line Items]
Loan commitments	$ 270,881	$ 195,229
Residential real estate
Concentration Risk [Line Items]
Loan commitments	91,141	29,622
Multifamily and commercial
Concentration Risk [Line Items]
Loan commitments	95,025	73,201
Commercial business loans
Concentration Risk [Line Items]
Loan commitments	18,737	13,000
Construction
Concentration Risk [Line Items]
Loan commitments	59,990	71,062
Home equity loans and advances
Concentration Risk [Line Items]
Loan commitments	$ 5,988	$ 8,344

Maximum amount of loss due to credit risk that, based on the gross fair value of the financial instrument, the entity would incur if parties to the financial instruments that make up the concentration failed completely to perform according to the terms of the contracts and the collateral or other security, if any, for the amount due proved to be of no value to the entity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13537-108611

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