Commitments and Contingencies - Financial Instruments Whose Contract Amounts Represent Credit Risk (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Commitments to grant loans
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments, contracts representing credit risk	$ 101	$ 625
Standby letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments, contracts representing credit risk	182	223
Unfunded commitments under lines of credit or existing loans
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments, contracts representing credit risk	$ 88,225	$ 98,847