Loans and Allowance for Loan Losses - Allowance for loan losses activity and recorded investment in loan by segment (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Allowance for loan losses:
Balance, beginning of period	$ 1,472,545	$ 1,404,988	$ 1,407,545	$ 1,405,072	$ 1,405,072
Provision (credit) charged to expense		25,000	65,000	25,000	25,000
Losses charged off		(22,443)		(22,527)
Recoveries					(22,527)
Balance, end of period	1,472,545	1,407,545	1,472,545	1,407,545	1,407,545
Ending balance: Individually evaluated for impairment	28,735		28,735		28,735
Ending balance: Collectively evaluated for impairment	1,443,810		1,443,810		1,378,810
Loans:
Ending balance	174,900,772		174,900,772		181,551,161
Ending balance: Individually evaluated for impairment	2,046,141		2,046,141		2,521,067
Ending balance: Collectively evaluated for impairment	172,854,631		172,854,631		179,030,094
Residential Portfolio Segment [Member]
Loans:
Ending balance					10,029,917
Residential Portfolio Segment [Member] | One- to Four- Family Mortgage Loans Owner Occupied [Member]
Allowance for loan losses:
Balance, beginning of period	449,513	456,630	324,647	456,630	456,630
Provision (credit) charged to expense	(71,172)	(81,169)	53,694	(81,169)	(117,552)
Losses charged off		(14,431)		(14,431)
Recoveries					(14,431)
Balance, end of period	378,341	361,030	378,341	361,030	324,647
Ending balance: Individually evaluated for impairment	20,722		20,722		20,722
Ending balance: Collectively evaluated for impairment	357,619		357,619		303,925
Loans:
Ending balance	79,018,999		79,018,999		91,919,064
Ending balance: Individually evaluated for impairment	1,160,983		1,160,983		1,115,573
Ending balance: Collectively evaluated for impairment	77,858,016		77,858,016		90,803,491
Residential Portfolio Segment [Member] | One To Four Family Investment Mortgage Loans [Member]
Allowance for loan losses:
Balance, beginning of period	97,741	123,017	82,219	123,017	123,017
Provision (credit) charged to expense	(14,173)	(27,962)	1,349	(27,962)	(32,786)
Losses charged off		(8,012)		(8,012)
Recoveries					(8,012)
Balance, end of period	83,568	87,043	83,568	87,043	82,219
Ending balance: Individually evaluated for impairment	8,013		8,013		8,013
Ending balance: Collectively evaluated for impairment	75,555		75,555		74,206
Loans:
Ending balance	12,570,884		12,570,884		12,846,342
Ending balance: Individually evaluated for impairment	569,212		569,212		760,733
Ending balance: Collectively evaluated for impairment	12,001,672		12,001,672		12,085,609
Residential Portfolio Segment [Member] | Multi-Family Mortgage Loans [Member]
Allowance for loan losses:
Balance, beginning of period	348,117	224,384	524,183	224,384	224,384
Provision (credit) charged to expense	20,655	138,667	(155,411)	138,667	299,799
Balance, end of period	368,772	363,051	368,772	363,051	524,183
Ending balance: Collectively evaluated for impairment	368,772		368,772		524,183
Loans:
Ending balance	38,680,588		38,680,588		36,628,238
Ending balance: Individually evaluated for impairment	213,116		213,116		507,066
Ending balance: Collectively evaluated for impairment	38,467,472		38,467,472		36,121,172
Residential Portfolio Segment [Member] | Real Estate Secured Lines of Credit [Member]
Allowance for loan losses:
Balance, beginning of period	65,722	296,873	105,187	296,873	296,873
Provision (credit) charged to expense	20,795	(1,320)	(18,670)	(1,320)	(191,686)
Balance, end of period	86,517	295,553	86,517	295,553	105,187
Ending balance: Collectively evaluated for impairment	86,517		86,517		105,187
Loans:
Ending balance	10,560,399		10,560,399		10,029,917
Ending balance: Individually evaluated for impairment	59,268		59,268		81,505
Ending balance: Collectively evaluated for impairment	10,501,131		10,501,131		9,948,412
Non Residential Portfolio Segment [Member]
Allowance for loan losses:
Balance, beginning of period	397,222	182,338	277,026	182,338	182,338
Provision (credit) charged to expense	37,054	6,201	157,250	6,201	94,688
Balance, end of period	434,276	188,539	434,276	188,539	277,026
Ending balance: Collectively evaluated for impairment	434,276		434,276		277,026
Loans:
Ending balance	26,728,087		26,728,087		23,377,598
Ending balance: Individually evaluated for impairment	43,562		43,562		56,190
Ending balance: Collectively evaluated for impairment	26,684,525		26,684,525		23,321,408
Commercial real estate portfolio segment [Member]
Loans:
Ending balance					5,329,188
Commercial real estate portfolio segment [Member] | Construction & Land Loans [Member]
Allowance for loan losses:
Balance, beginning of period	75,594	100,187	69,457	100,187	100,187
Provision (credit) charged to expense	9,348	(10,142)	15,485	(10,142)	(30,730)
Balance, end of period	84,942	90,045	84,942	90,045	69,457
Ending balance: Collectively evaluated for impairment	84,942		84,942		69,457
Loans:
Ending balance	5,611,889		5,611,889		5,329,188
Ending balance: Collectively evaluated for impairment	5,611,889		5,611,889		5,329,188
Commercial Loans [Member]
Allowance for loan losses:
Balance, beginning of period	32,220	9,001	11,408	9,001	9,001
Provision (credit) charged to expense	(1,732)	(1,443)	19,080	(1,443)	2,407
Balance, end of period	30,488	7,558	30,488	7,558	11,408
Ending balance: Collectively evaluated for impairment	30,488		30,488		11,408
Loans:
Ending balance	1,396,309		1,396,309		557,268
Ending balance: Collectively evaluated for impairment	1,396,309		1,396,309		557,268
Other Consumer Loans [Member]
Allowance for loan losses:
Balance, beginning of period	6,416	12,558	13,418	12,642	12,642
Provision (credit) charged to expense	(775)	2,168	(7,777)	2,168	860
Losses charged off				(84)
Recoveries					(84)
Balance, end of period	5,641	$ 14,726	5,641	$ 14,726	13,418
Ending balance: Collectively evaluated for impairment	5,641		5,641		13,418
Loans:
Ending balance	333,617		333,617		863,546
Ending balance: Collectively evaluated for impairment	$ 333,617		$ 333,617		$ 863,546