Loans and Allowance for Loan Losses - Credit risk profile (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 174,900,772	$ 181,551,161
Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	172,813,297	179,087,898
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,165,522	1,112,716
Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	921,953	1,350,547
Residential Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans		10,029,917
Residential Portfolio Segment [Member] | One- to Four- Family Mortgage Loans Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	79,018,999	91,919,064
Residential Portfolio Segment [Member] | One- to Four- Family Mortgage Loans Owner Occupied [Member] | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	78,330,038	91,281,765
Residential Portfolio Segment [Member] | One- to Four- Family Mortgage Loans Owner Occupied [Member] | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	115,200
Residential Portfolio Segment [Member] | One- to Four- Family Mortgage Loans Owner Occupied [Member] | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	573,761	637,299
Residential Portfolio Segment [Member] | One To Four Family Investment Mortgage Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	12,570,884	12,846,342
Residential Portfolio Segment [Member] | One To Four Family Investment Mortgage Loans [Member] | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	11,927,786	12,115,427
Residential Portfolio Segment [Member] | One To Four Family Investment Mortgage Loans [Member] | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	528,524	548,876
Residential Portfolio Segment [Member] | One To Four Family Investment Mortgage Loans [Member] | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	114,574	182,039
Residential Portfolio Segment [Member] | Multi-Family Mortgage Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	38,680,588	36,628,238
Residential Portfolio Segment [Member] | Multi-Family Mortgage Loans [Member] | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	38,599,760	36,256,469
Residential Portfolio Segment [Member] | Multi-Family Mortgage Loans [Member] | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	80,828	371,769
Residential Portfolio Segment [Member] | Real Estate Secured Lines of Credit [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	10,560,399	10,029,917
Residential Portfolio Segment [Member] | Real Estate Secured Lines of Credit [Member] | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	10,407,609	9,870,477
Residential Portfolio Segment [Member] | Real Estate Secured Lines of Credit [Member] | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	152,790	159,440
Non Residential Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	26,728,087	23,377,598
Non Residential Portfolio Segment [Member] | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	26,206,289	22,813,758
Non Residential Portfolio Segment [Member] | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	521,798	563,840
Commercial real estate portfolio segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans		5,329,188
Commercial real estate portfolio segment [Member] | Construction & Land Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,611,889	5,329,188
Commercial real estate portfolio segment [Member] | Construction & Land Loans [Member] | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,611,889	5,329,188
Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,396,309	557,268
Commercial Loans [Member] | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,396,309	557,268
Other Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	333,617	863,546
Other Consumer Loans [Member] | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 333,617	$ 863,546