Fair Value Measurement - Balance Sheet Grouping (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Carrying Amount
Financial assets:
Cash and cash equivalents	$ 87,133	$ 108,408
Investment securities:
HTM, at carrying value	788	907
Mortgage-backed securities:
HTM, at carrying value	91,691	108,091
FHLB stock, at cost	27,248	25,259
Equity investments	5,818	5,811
Loans, net of allowance for loan losses	3,609,563	3,608,773
Loans held for sale	1,131	3,695
Financial liabilities:
Deposits	5,331,655	4,932,322
Other borrowings	20,724	23,172
FHLB borrowings	659,204	832,527
Subordinated notes, net of unamortized debt issuance costs	98,500	197,251
Trust preferred subordinated debentures, net of unamortized debt issuance costs	60,259	60,255
Estimated Fair Value
Financial assets:
Cash and cash equivalents	87,133	108,408
Investment securities:
HTM, at carrying value	791	920
Mortgage-backed securities:
HTM, at carrying value	97,244	117,278
FHLB stock, at cost	27,248	25,259
Equity investments	5,818	5,811
Loans, net of allowance for loan losses	3,755,534	3,784,291
Loans held for sale	1,131	3,695
Financial liabilities:
Deposits	5,333,064	4,936,188
Other borrowings	20,724	23,172
FHLB borrowings	668,232	854,865
Subordinated notes, net of unamortized debt issuance costs	98,722	198,391
Trust preferred subordinated debentures, net of unamortized debt issuance costs	48,436	51,993
Estimated Fair Value | Level 1
Financial assets:
Cash and cash equivalents	87,133	108,408
Investment securities:
HTM, at carrying value	0	0
Mortgage-backed securities:
HTM, at carrying value	0	0
FHLB stock, at cost	0	0
Equity investments	0	0
Loans, net of allowance for loan losses	0	0
Loans held for sale	0	0
Financial liabilities:
Deposits	0	0
Other borrowings	0	0
FHLB borrowings	0	0
Subordinated notes, net of unamortized debt issuance costs	0	0
Trust preferred subordinated debentures, net of unamortized debt issuance costs	0	0
Estimated Fair Value | Level 2
Financial assets:
Cash and cash equivalents	0	0
Investment securities:
HTM, at carrying value	791	920
Mortgage-backed securities:
HTM, at carrying value	97,244	117,278
FHLB stock, at cost	27,248	25,259
Equity investments	5,818	5,811
Loans, net of allowance for loan losses	0	0
Loans held for sale	1,131	3,695
Financial liabilities:
Deposits	5,333,064	4,936,188
Other borrowings	20,724	23,172
FHLB borrowings	668,232	854,865
Subordinated notes, net of unamortized debt issuance costs	98,722	198,391
Trust preferred subordinated debentures, net of unamortized debt issuance costs	48,436	51,993
Estimated Fair Value | Level 3
Financial assets:
Cash and cash equivalents	0	0
Investment securities:
HTM, at carrying value	0	0
Mortgage-backed securities:
HTM, at carrying value	0	0
FHLB stock, at cost	0	0
Equity investments	0	0
Loans, net of allowance for loan losses	3,755,534	3,784,291
Loans held for sale	0	0
Financial liabilities:
Deposits	0	0
Other borrowings	0	0
FHLB borrowings	0	0
Subordinated notes, net of unamortized debt issuance costs	0	0
Trust preferred subordinated debentures, net of unamortized debt issuance costs	$ 0	$ 0