Fair Value Measurements - Fair Values of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financial assets:
Securities available-for-sale	$ 142,539	$ 146,991
Securities held-to-maturity	22,685	21,760
Carrying Value
Financial assets:
Interest-bearing deposits in other financial institutions	114,205	138,152
Securities available-for-sale	142,539	146,991
Securities held-to-maturity	22,685	21,760
Loans held-for-sale	440	5,781
Net loans held-for-investment	1,382,229	1,325,515
FHLB and other restricted stock	8,345	7,433
Accrued interest receivable	5,314	5,178
Financial liabilities:
Deposits	1,446,526	1,443,753
FHLB advances	35,000	30,000
Accrued interest payable	5,343	6,223
Fair Value
Financial assets:
Interest-bearing deposits in other financial institutions	114,205	138,152
Securities available-for-sale	142,539	146,991
Securities held-to-maturity	22,813	21,152
Loans held-for-sale	449	6,175
Net loans held-for-investment	1,391,534	1,337,299
Accrued interest receivable	5,314	5,178
Financial liabilities:
Deposits	1,451,505	1,425,023
FHLB advances	35,075	29,641
Accrued interest payable	5,343	6,223
Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets:
Interest-bearing deposits in other financial institutions	114,205	138,152
Securities available-for-sale	0	0
Securities held-to-maturity	0	0
Loans held-for-sale	0	0
Net loans held-for-investment	0	0
Accrued interest receivable	83	112
Financial liabilities:
Deposits	0	0
FHLB advances	0	0
Accrued interest payable	0	0
Fair Value | Significant Other Observable Inputs (Level 2)
Financial assets:
Interest-bearing deposits in other financial institutions	0	0
Securities available-for-sale	142,539	146,991
Securities held-to-maturity	22,813	21,152
Loans held-for-sale	449	6,175
Net loans held-for-investment	0	0
Accrued interest receivable	551	568
Financial liabilities:
Deposits	0	0
FHLB advances	35,075	29,641
Accrued interest payable	36	1
Fair Value | Significant Unobservable Inputs (Level 3)
Financial assets:
Interest-bearing deposits in other financial institutions	0	0
Securities available-for-sale	0	0
Securities held-to-maturity	0	0
Loans held-for-sale	0	0
Net loans held-for-investment	1,391,534	1,337,299
Accrued interest receivable	4,680	4,498
Financial liabilities:
Deposits	1,451,505	1,425,023
FHLB advances	0	0
Accrued interest payable	$ 5,307	$ 6,222