Regulatory Matters (Regulatory capital amounts and ratios) (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Tier 1 Risk-Based Core Capital (To Risk Weighted Assets)
Actual, Amount	$ 75,120	$ 73,787,109
Actual, Ratio	16.80%	16.60%
For Capital Adequacy, Amount	$ 26,883	$ 26,713,714
For Capital Adequacy, Ratio	6.00%	6.00%
Total Risk-Based Capital (To Risk Weighted Assets)
Actual, Amount	$ 80,753	$ 79,383,109
Actual, Ratio	18.00%	17.80%
For Capital Adequacy, Amount	$ 35,844	$ 35,618,286
For Capital Adequacy, Ratio	8.00%	8.00%
Common Equity Tier One Capital	$ 70,120
Tier 1 Leverage (Core) Capital (To Adjusted Tangible Assets)
Actual, Amount	$ 75,120	$ 73,787,000
Actual, Ratio	9.20%	9.10%
For Capital Adequacy, Amount	$ 32,804	$ 32,548,106
For Capital Adequacy, Ratio	4.00%	4.00%
Security Federal Bank [Member]
Tier 1 Risk-Based Core Capital (To Risk Weighted Assets)
Actual, Amount	$ 88,270,000	$ 88,139,000
Actual, Ratio	19.70%	19.80%
For Capital Adequacy, Amount	$ 26,872,560	$ 26,694,000
For Capital Adequacy, Ratio	6.00%	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 35,830	$ 35,592,000
To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	8.00%	8.00%
Total Risk-Based Capital (To Risk Weighted Assets)
Actual, Amount	$ 93,903,000	$ 93,735,000
Actual, Ratio	21.00%	21.10%
For Capital Adequacy, Amount	$ 35,830,080	$ 35,592,000
For Capital Adequacy, Ratio	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 44,788	$ 44,490,000
To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.00%	10.00%
Common Equity Tier One Capital	$ 88,270,000
Tier 1 Leverage (Core) Capital (To Adjusted Tangible Assets)
Actual, Amount	$ 88,270,000	$ 88,139,000
Actual, Ratio	10.80%	10.80%
For Capital Adequacy, Amount	$ 32,797,320	$ 32,586,840
For Capital Adequacy, Ratio	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 40,997	$ 40,733,550
To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%	5.00%