Fair Value Measurements - Summary of estimated fair values of financial instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financial Assets:
Securities purchased under agreements to resell, at cost	$ 50,225	$ 50,271
Securities available for sale	111,375	148,384
Securities, held to maturity	80,102	0
Securities, restricted, at cost	2,810	2,680
Loans held for investment, net	864,229	775,441
Accrued interest receivable	5,228	4,197
Financial Liabilities:
Time deposits	18,928	19,312
Carrying Value
Financial Assets:
Cash and cash equivalents	182,125	149,156
Securities purchased under agreements to resell, at cost	50,225	50,271
Securities, held to maturity	80,102
Securities, restricted, at cost	2,810	2,680
Loans held for investment, net	864,229	775,441
Accrued interest receivable	5,228	4,197
Financial Liabilities:
Time deposits	18,928	19,312
Demand and other deposits	1,168,529	1,009,097
Secured borrowings	47	48
Accrued interest payable	10
Fair Value
Financial Assets:
Cash and cash equivalents	182,125	149,156
Securities purchased under agreements to resell, at cost	50,225	50,271
Securities, held to maturity	71,436
Loans held for investment, net	856,612	774,114
Accrued interest receivable	5,026	4,197
Financial Liabilities:
Time deposits	18,813	19,330
Demand and other deposits	1,168,529	1,009,097
Secured borrowings	47	48
Accrued interest payable	10
Fair Value | (Level 1)
Financial Assets:
Cash and cash equivalents	1,217	2,202
Loans held for investment, net	0	0
Accrued interest receivable	0	0
Financial Liabilities:
Time deposits		0
Demand and other deposits	1,168,529	1,009,097
Secured borrowings	0	0
Accrued interest payable	0
Fair Value | (Level 2)
Financial Assets:
Cash and cash equivalents	180,908	146,954
Securities, held to maturity	71,436
Loans held for investment, net	0	0
Accrued interest receivable	298	252
Financial Liabilities:
Time deposits	18,813	19,330
Demand and other deposits	0	0
Secured borrowings	47	48
Accrued interest payable	10
Fair Value | (Level 3)
Financial Assets:
Cash and cash equivalents	0	0
Securities purchased under agreements to resell, at cost	50,225	50,271
Loans held for investment, net	856,612	774,114
Accrued interest receivable	4,728	3,945
Financial Liabilities:
Time deposits		0
Demand and other deposits	0	0
Secured borrowings	0	$ 0
Accrued interest payable	$ 0