Commitments and Contingencies - Summary of Distribution of Undisbursed Loan Commitments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Undisbursed loan commitments	$ 85,353	$ 74,641
Commitments to Extend Credit
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Undisbursed loan commitments	74,146	66,153
Standby Letter of Credit
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Undisbursed loan commitments	9,722	7,377
Commercial Letter of Credit
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Undisbursed loan commitments	$ 1,485	$ 1,111