Commitments and Contingencies - Summary of Distribution of Undisbursed Loan Commitments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Undisbursed loan commitments	$ 68,933	$ 63,788
Standby Letter of Credit
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Undisbursed loan commitments	895	1,790
Commercial Letter of Credit
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Undisbursed loan commitments	1,035	1,209
Commitments to Extend Credit
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Undisbursed loan commitments	$ 67,003	$ 60,789