Note 5 - Loans and Allowance for Loan Losses - Loans by Aging (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Loans receivable, past due	$ 6,139,000	$ 1,356,000
Loans receivable, current	723,659,000	727,558,000
Loans receivable	729,798,445	728,914,025
Loans receivable, past due and accruing
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Loans receivable, past due	1,497,000	645,000
Loans receivable, current	122,891,000	118,179,000
Loans receivable	124,387,549	118,823,731
Loans receivable, past due and accruing
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Loans receivable, past due
Loans receivable, current	82,549,000	87,448,000
Loans receivable	82,548,977	87,448,418
Loans receivable, past due and accruing
Real Estate, Construction [Member]
Loans receivable, past due	1,825,000	338,000
Loans receivable, current	71,289,000	76,971,000
Loans receivable	73,114,249	77,308,551
Loans receivable, past due and accruing
Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due	2,152,000	43,000
Loans receivable, current	298,553,000	300,576,000
Loans receivable	300,704,999	300,619,387
Loans receivable, past due and accruing
Commercial Portfolio Segment [Member]
Loans receivable, past due	418,000	256,000
Loans receivable, current	117,763,000	113,792,000
Loans receivable	118,181,468	114,047,753
Loans receivable, past due and accruing
Consumer and Other Loans [Member]
Loans receivable, past due	247,000	74,000
Loans receivable, current	30,614,000	30,592,000
Loans receivable	30,861,203	30,666,185
Loans receivable, past due and accruing
Financial Asset, 30 to 59 Days Past Due [Member]
Loans receivable, past due	4,273,000	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	837,000	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
Financial Asset, 30 to 59 Days Past Due [Member] | Real Estate, Construction [Member]
Loans receivable, past due	1,825,000	338,000
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due	1,549,000
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans receivable, past due	31,000	134,000
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer and Other Loans [Member]
Loans receivable, past due	31,000	48,000
Financial Asset, 60 to 89 Days Past Due [Member]
Loans receivable, past due	417,000	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		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
Financial Asset, 60 to 89 Days Past Due [Member] | Real Estate, Construction [Member]
Loans receivable, past due
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due	244,000
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans receivable, past due	173,000	105,000
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer and Other Loans [Member]
Loans receivable, past due		26,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans receivable, past due	1,449,000	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	660,000	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
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate, Construction [Member]
Loans receivable, past due
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans receivable, past due	359,000	43,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans receivable, past due	214,000	17,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer and Other Loans [Member]
Loans receivable, past due	$ 216,000