Stockholders' Equity - Summary of capital comparison with minimum requirements (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jan. 01, 2016
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Annual increase in capital (to risk weighted assets) for capital adequacy purposes ratio	0.625%
Common Equity Tier I Capital (to Risk Weighted Assets) Actual Amount	$ 36,442	$ 35,693
Common Equity Tier I Capital (to Risk Weighted Assets) Actual Ratio	13.09%	12.47%
Common Equity Tier I Capital (to Risk Weighted Assets) For Capital Adequacy Purposes Actual Amount	$ 12,532	$ 12,878
Common Equity Tier I Capital (to Risk Weighted Assets) For Capital Adequacy Purposes Actual Ratio	4.50%	4.50%
Common Equity Tier I Capital (to Risk Weighted Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Actual Amount	$ 18,101	$ 18,602
Common Equity Tier I Capital (to Risk Weighted Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Actual Ratio	6.50%	6.50%
Total Capital (to Risk Weighted Assets) Actual Amount	$ 37,951	$ 37,797
Total Capital (to Risk Weighted Assets) Actual Ratio	13.63	13.21
Total Capital (to Risk Weighted Assets) For Capital Adequacy Purposes Amount	$ 22,278	$ 22,895
Total Capital (to Risk Weighted Assets) For Capital Adequacy Purposes Ratio	8.00	8.00	0.625
Total Capital (to Risk Weighted Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 27,848	$ 28,619
Total Capital (to Risk Weighted Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	10.00	10.00
Tier I Capital (to Risk Weighted Assets) Actual Amount	$ 36,442	$ 35,693
Tier I Capital (to Risk Weighted Assets) Actual Ratio	13.09	12.47
Tier I Capital (to Risk Weighted Assets) For Capital Adequacy Purposes Amount	$ 16,709	$ 17,171
Tier I Capital (to Risk Weighted Assets) For Capital Adequacy Purposes Ratio	6.00	6.00
Tier I Capital (to Risk Weighted Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 22,278	$ 22,895
Tier I Capital (to Risk Weighted Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	8.00	8.00
Tier I Capital (to Average Assets) Actual Amount	$ 36,442	$ 35,693
Tier I Capital (to Average Assets) Actual Ratio	9.12	9.26
Tier I Capital (to Average Assets) For Capital Adequacy Purposes Amount	$ 15,980	$ 15,414
Tier I Capital (to Average Assets) For Capital Adequacy Purposes Ratio	4.00	4.00
Tier I Capital (to Average Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 19,975	$ 19,268
Tier I Capital (to Average Assets) To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	5.00	5.00
Minimum
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets) Actual Ratio	8.0
Tier I Capital (to Risk Weighted Assets) Actual Ratio	4.0
Tier I Capital (to Average Assets) Actual Ratio	4.0
Maximum
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets) For Capital Adequacy Purposes Ratio	2.5
Tier I Capital (to Risk Weighted Assets) Actual Ratio	6.0