FAIR VALUE MEASUREMENT - Fair Value, Balance Sheet Grouping (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Carrying Amount
Financial Assets
Cash and cash equivalents	$ 108,408	$ 110,697
Investment securities:
HTM, at carrying value	907	2,888
Mortgage-backed securities:
HTM, at carrying value	108,091	131,975
FHLB stock, at cost	25,259	50,087
Equity investments	5,811	6,366
Loans, net of allowance for loan losses	3,608,773	3,543,407
Loans held for sale	3,695	383
Financial Liabilities:
Deposits	4,932,322	4,702,769
Other borrowings	23,172	28,358
FHLB borrowings	832,527	972,744
Subordinated notes, net of unamortized debt issuance costs	197,251	98,576
Trust preferred subordinated debentures, net of unamortized debt issuance costs	60,255	60,250
Estimated Fair Value
Financial Assets
Cash and cash equivalents	108,408	110,697
Investment securities:
HTM, at carrying value	920	2,918
Mortgage-backed securities:
HTM, at carrying value	117,278	135,961
FHLB stock, at cost	25,259	50,087
Equity investments	5,811	6,366
Loans, net of allowance for loan losses	3,784,291	3,610,591
Loans held for sale	3,695	383
Financial Liabilities:
Deposits	4,936,188	4,703,914
Other borrowings	23,172	28,358
FHLB borrowings	854,865	975,606
Subordinated notes, net of unamortized debt issuance costs	198,391	98,346
Trust preferred subordinated debentures, net of unamortized debt issuance costs	51,993	55,937
Estimated Fair Value | Level 1
Financial Assets
Cash and cash equivalents	108,408	110,697
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	920	2,918
Mortgage-backed securities:
HTM, at carrying value	117,278	135,961
FHLB stock, at cost	25,259	50,087
Equity investments	5,811	6,366
Loans, net of allowance for loan losses	0	0
Loans held for sale	3,695	383
Financial Liabilities:
Deposits	4,936,188	4,703,914
Other borrowings	23,172	28,358
FHLB borrowings	854,865	975,606
Subordinated notes, net of unamortized debt issuance costs	198,391	98,346
Trust preferred subordinated debentures, net of unamortized debt issuance costs	51,993	55,937
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	3,784,291	3,610,591
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