Fair Values of Financial Instruments - Financial Instruments Not Disclosed Elsewhere (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Carrying Amount
Financial assets:
Loans, net	$ 639,649	$ 625,513
Financial liabilities:
Interest-bearing deposits	639,516	614,925
FHLB advances and notes payable	55,660	56,989
Estimated Fair Value
Financial assets:
Loans, net	619,552	604,290
Financial liabilities:
Interest-bearing deposits	606,769	570,509
FHLB advances and notes payable	56,267	56,979
Estimated Fair Value | Level 2
Financial liabilities:
Interest-bearing deposits	606,769	570,509
FHLB advances and notes payable	56,267	56,979
Estimated Fair Value | Level 3
Financial assets:
Loans, net	$ 619,552	$ 604,290