Fair Value Measurements and Disclosures - Estimated fair values of financial instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financial assets:
Securities available-for-sale	$ 123,562	$ 58,856
Securities held-to-maturity	6,857	9,003
Equity investments	1,031	1,009
Mortgage loans held-for-investment	12,182	10,546
Carrying amount
Financial assets:
Restricted investment in bank stock	7,861	8,072
Level 1 | Carrying amount
Financial assets:
Cash and cash equivalents	36,744	39,371
Level 1 | Fair value
Financial assets:
Cash and cash equivalents	36,744	39,371
Level 2 | Carrying amount
Financial assets:
Securities available-for-sale	123,562	58,856
Securities held-to-maturity	6,510	8,780
Equity investments	1,031	1,009
Mortgage loans held-for-sale	229,199	33,704
Mortgage loans held-for-investment	12,182	10,546
Financial liabilities:
Deposits	1,241,335	851,168
Short-term borrowings	106,862	123,676
Long-term debt	165,546	3,123
Subordinated debentures	40,671	40,962
Accrued interest payable	1,154	1,088
Level 2 | Carrying amount | Forward Commitments
Financial assets:
Derivative asset		6
Financial liabilities:
Derivatives	1,572	119
Level 2 | Carrying amount | Customer derivatives - interest rate swaps
Financial assets:
Derivative asset	1,118	382
Financial liabilities:
Derivatives	1,219	431
Level 2 | Fair value
Financial assets:
Securities available-for-sale	123,562	58,856
Securities held-to-maturity	6,857	9,003
Equity investments	1,031	1,009
Mortgage loans held-for-sale	229,199	33,704
Mortgage loans held-for-investment	12,182	10,546
Financial liabilities:
Deposits	1,392,500	880,400
Short-term borrowings	106,862	123,678
Long-term debt	168,000	3,123
Subordinated debentures	38,375	40,962
Accrued interest payable	1,154	1,088
Level 2 | Fair value | Forward Commitments
Financial assets:
Derivative asset		6
Financial liabilities:
Derivatives	1,572	119
Level 2 | Fair value | Customer derivatives - interest rate swaps
Financial assets:
Derivative asset	1,118	382
Financial liabilities:
Derivatives	1,219	431
Level 3 | Interest rate lock commitments
Financial assets:
Derivative asset	6,932	504
Level 3 | Carrying amount
Financial assets:
Loans receivable, net of the allowance and lease losses	1,272,582	954,164
Accrued interest receivable	5,482	3,148
Level 3 | Carrying amount | Interest rate lock commitments
Financial assets:
Derivative asset	6,932	504
Financial liabilities:
Derivatives	100	157
Level 3 | Fair value
Financial assets:
Loans receivable, net of the allowance and lease losses	1,289,776	973,057
Accrued interest receivable	5,482	3,148
Level 3 | Fair value | Interest rate lock commitments
Financial assets:
Derivative asset	6,932	504
Financial liabilities:
Derivatives	$ 100	$ 157