Note 4 - Loans and Allowance for Loan Losses - Loans by Aging (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Loans receivable, past due	$ 13,504,000	$ 1,356,000
Loans receivable, current	739,904,000	727,558,000
Loans receivable	753,408,413	728,914,025
Loans receivable, past due and accruing	0	0
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable, past due	2,752,000	645,000
Loans receivable, current	113,047,000	118,179,000
Loans receivable	115,799,200	118,823,731
Loans receivable, past due and accruing	0	0
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable, past due	0	0
Loans receivable, current	90,029,000	87,448,000
Loans receivable	90,028,775	87,448,418
Loans receivable, past due and accruing	0	0
Real Estate, Construction [Member]
Loans receivable, past due	5,428,000	338,000
Loans receivable, current	65,419,000	76,971,000
Loans receivable	70,847,330	77,308,551
Loans receivable, past due and accruing	0	0
Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due	501,000	43,000
Loans receivable, current	305,172,000	300,576,000
Loans receivable	305,673,212	300,619,387
Loans receivable, past due and accruing	0	0
Commercial Portfolio Segment [Member]
Loans receivable, past due	4,791,000	256,000
Loans receivable, current	139,535,000	113,792,000
Loans receivable	144,326,350	114,047,753
Loans receivable, past due and accruing	0	0
Consumer and Other Loans [Member]
Loans receivable, past due	32,000	74,000
Loans receivable, current	26,702,000	30,592,000
Loans receivable	26,733,546	30,666,185
Loans receivable, past due and accruing	0	0
Financial Asset, 30 to 59 Days Past Due [Member]
Loans receivable, past due	2,142,000	603,000
Financial Asset, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable, past due	623,000	83,000
Financial Asset, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable, past due	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Real Estate, Construction [Member]
Loans receivable, past due	1,239,000	338,000
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due	264,000	0
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans receivable, past due	6,000	134,000
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer and Other Loans [Member]
Loans receivable, past due	10,000	48,000
Financial Asset, 60 to 89 Days Past Due [Member]
Loans receivable, past due	1,136,000	568,000
Financial Asset, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable, past due	1,058,000	437,000
Financial Asset, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable, past due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Real Estate, Construction [Member]
Loans receivable, past due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due	76,000	0
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans receivable, past due	1,000	105,000
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer and Other Loans [Member]
Loans receivable, past due	1,000	26,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans receivable, past due	10,226,000	185,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable, past due	1,071,000	125,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable, past due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate, Construction [Member]
Loans receivable, past due	4,189,000	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due	161,000	43,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans receivable, past due	4,784,000	17,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer and Other Loans [Member]
Loans receivable, past due	$ 21,000	$ 0