Fair Value of Financial Instruments - Carrying values and fair values of financial instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financial Assets:
Federal funds sold	$ 8,097	$ 4,258
Marketable equity securities	2,185	2,207
Available for sale securities	87,565	88,605
Held to maturity securities	16,107	16,078
Derivative asset	2,893	4,484
Financial Liabilities:
Derivative liability	18,375	28,673
Level 1
Financial Assets:
Cash and due from banks	169,417	405,340
Federal funds sold	8,097	4,258
Marketable equity securities	2,185	2,207
Available for sale securities	20,568	10,148
Held to maturity securities	0	0
Loans receivable, net	0	0
Accrued interest receivable	0	0
FHLB stock	0	0
Servicing asset, net of valuation allowance	0	0
Derivative asset	0	0
Assets held for sale	0	0
Financial Liabilities:
Noninterest bearing deposits	0	0
NOW and money market	0	0
Savings	0	0
Time deposits	0	0
Accrued interest payable	0	0
Advances from the FHLB	0	0
Subordinated debentures	0	0
Servicing liability	0	0
Derivative liability	0	0
Level 2
Financial Assets:
Cash and due from banks	0	0
Federal funds sold	0	0
Marketable equity securities	0	0
Available for sale securities	66,997	78,457
Held to maturity securities	57	70
Loans receivable, net	0	0
Accrued interest receivable	6,911	6,579
FHLB stock	3,632	7,860
Servicing asset, net of valuation allowance	0	0
Derivative asset	2,917	4,444
Assets held for sale	0	0
Financial Liabilities:
Noninterest bearing deposits	338,705	270,235
NOW and money market	938,390	771,101
Savings	188,581	158,750
Time deposits	0	0
Accrued interest payable	933	1,750
Advances from the FHLB	0	0
Subordinated debentures	0	0
Servicing liability	0	0
Derivative liability	17,813	28,011
Level 3
Financial Assets:
Cash and due from banks	0	0
Federal funds sold	0	0
Marketable equity securities	0	0
Available for sale securities	0	0
Held to maturity securities	18,303	19,962
Loans receivable, net	1,792,793	1,605,402
Accrued interest receivable	0	0
FHLB stock	0	0
Servicing asset, net of valuation allowance	813	628
Derivative asset	0	0
Assets held for sale	2,613	2,613
Financial Liabilities:
Noninterest bearing deposits	0	0
NOW and money market	0	0
Savings	0	0
Time deposits	418,703	631,891
Accrued interest payable	0	0
Advances from the FHLB	79,998	174,997
Subordinated debentures	15,500	25,447
Servicing liability	13	21
Derivative liability	0	0
Carrying Value
Financial Assets:
Cash and due from banks	169,417	405,340
Federal funds sold	8,097	4,258
Marketable equity securities	2,185	2,207
Available for sale securities	87,565	88,605
Held to maturity securities	16,107	16,078
Loans receivable, net	1,805,217	1,601,672
Accrued interest receivable	6,911	6,579
FHLB stock	3,632	7,860
Servicing asset, net of valuation allowance	813	628
Derivative asset	2,917	4,444
Assets held for sale	2,613	2,613
Financial Liabilities:
Noninterest bearing deposits	338,705	270,235
NOW and money market	938,390	771,101
Savings	188,581	158,750
Time deposits	417,147	627,230
Accrued interest payable	933	1,750
Advances from the FHLB	80,000	175,000
Subordinated debentures	15,500	25,258
Servicing liability	13	21
Derivative liability	17,813	28,011
Fair Value
Financial Assets:
Cash and due from banks	169,417	405,340
Federal funds sold	8,097	4,258
Marketable equity securities	2,185	2,207
Available for sale securities	87,565	88,605
Held to maturity securities	18,360	20,032
Loans receivable, net	1,792,793	1,605,402
Accrued interest receivable	6,911	6,579
FHLB stock	3,632	7,860
Servicing asset, net of valuation allowance	813	628
Derivative asset	2,917	4,444
Assets held for sale	2,613	2,613
Financial Liabilities:
Noninterest bearing deposits	338,705	270,235
NOW and money market	938,390	771,101
Savings	188,581	158,750
Time deposits	418,703	631,891
Accrued interest payable	933	1,750
Advances from the FHLB	79,998	174,997
Subordinated debentures	15,500	25,447
Servicing liability	13	21
Derivative liability	$ 17,813	$ 28,011