Regulatory Capital - Schedule of bank's capital levels (Details) $ in Thousands	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Actual Capital Amount [Abstract]
Total capital (to risk-weighted assets), Actual amount	$ 190,718	$ 143,021
Total capital (to risk-weighted assets), Minimum Capital Adequacy amount	95,870	83,399
Total capital (to risk-weighted assets), For Classification as Well-Capitalized amount	$ 119,837	$ 104,249
Actual Capital Ratio [Abstract]
Total capital (to risk-weighted assets), Actual ratio	15.91	13.72
Total capital (to risk-weighted assets), Minimum Capital Adequacy ratio	8.00	8.00
Total capital (to risk-weighted assets), For Classification as Well-Capitalized ratio	10.00	10.00
Tier 1 capital Amount [Abstract]
Tier 1 capital (to risk-weighted assets), Actual amount	$ 185,505	$ 137,962
Tier 1 capital (to risk-weighted assets), Minimum Capital Adequacy amount	71,902	62,550
Tier 1 capital (to risk-weighted assets), For Classification as Well-Capitalized amount	$ 95,870	$ 83,399
Tier 1 capital Ratio [Abstract]
Tier 1 capital (to risk-weighted assets), Actual ratio	15.48	13.23
Tier 1 capital (to risk-weighted assets), Minimum Capital Adequacy ratio	6.00	6.00
Tier 1 capital (to risk-weighted assets), For Classification as Well-Capitalized ratio	8.00	8.00
Common Equity Tier 1 Capital Amount [Abstract]
Common equity tier 1 capital (to risk-weighted assets), Actual amount	$ 185,505	$ 137,962
Common equity tier 1 capital (to risk-weighted assets), Minimum Capital Adequacy amount	53,927	46,912
Common equity tier 1 capital (to risk-weighted assets), For Classification as Well-Capitalized amount	$ 77,894	$ 67,762
Common Equity Tier 1 Capital Ratio [Abstract]
Common equity tier 1 capital (to risk-weighted assets), Actual ratio	15.48	13.23
Common equity tier 1 capital (to risk-weighted assets), Minimum Capital Adequacy ratio	4.50	4.50
Common equity tier 1 capital (to risk-weighted assets), For Classification as Well-Capitalized ratio	6.50	6.50
Core (Tier 1) Capital Amount [Abstract]
Core (Tier 1) capital (to adjusted total assets), Actual amount	$ 185,505	$ 137,962
Core (Tier 1) capital (to adjusted total assets), Minimum Capital Adequacy amount	43,476	37,304
Core (Tier 1) capital (to adjusted total assets), For Classification as Well-Capitalized amount	$ 54,345	$ 46,629
Core (Tier 1) Capital Ratio [Abstract]
Core (Tier 1) capital (to adjusted total assets), Actual ratio	17.07	14.79
Core (Tier 1) capital (to adjusted total assets), Minimum Capital Adequacy ratio	4.00	4.00
Core (Tier 1) capital (to adjusted total assets), For Classification as Well-Capitalized ratio	5.00	5.00

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