Note 4 - Loans and Allowance for Loan Losses - Troubled Debt Restructurings (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Number of loans	1	3
Pre-modification outstanding recorded balance	$ 193,437	$ 540,550
Post-modification outstanding recorded balance	193,437	444,645
Interest Rate [Member]
Post-modification outstanding recorded balance	0	0
Term [Member]
Post-modification outstanding recorded balance	193,437	30,130
Combination [Member]
Post-modification outstanding recorded balance		$ 414,515
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Number of loans	0	0
Pre-modification outstanding recorded balance	$ 0	$ 0
Post-modification outstanding recorded balance	0	0
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member] | Interest Rate [Member]
Post-modification outstanding recorded balance	0	0
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member] | Term [Member]
Post-modification outstanding recorded balance	0	0
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member] | Combination [Member]
Post-modification outstanding recorded balance	$ 0	$ 0
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Number of loans	0	0
Pre-modification outstanding recorded balance	$ 0	$ 0
Post-modification outstanding recorded balance	0	0
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member] | Interest Rate [Member]
Post-modification outstanding recorded balance	0	0
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member] | Term [Member]
Post-modification outstanding recorded balance	0	0
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member] | Combination [Member]
Post-modification outstanding recorded balance	$ 0	$ 0
Real Estate, Construction [Member]
Number of loans	0	0
Pre-modification outstanding recorded balance	$ 0	$ 0
Post-modification outstanding recorded balance	0	0
Real Estate, Construction [Member] | Interest Rate [Member]
Post-modification outstanding recorded balance	0	0
Real Estate, Construction [Member] | Term [Member]
Post-modification outstanding recorded balance	0	0
Real Estate, Construction [Member] | Combination [Member]
Post-modification outstanding recorded balance	$ 0	$ 0
Commercial Real Estate Portfolio Segment [Member]
Number of loans	0	0
Pre-modification outstanding recorded balance	$ 0	$ 0
Post-modification outstanding recorded balance	0	0
Commercial Real Estate Portfolio Segment [Member] | Interest Rate [Member]
Post-modification outstanding recorded balance	0	0
Commercial Real Estate Portfolio Segment [Member] | Term [Member]
Post-modification outstanding recorded balance	0	0
Commercial Real Estate Portfolio Segment [Member] | Combination [Member]
Post-modification outstanding recorded balance	$ 0	$ 0
Commercial Portfolio Segment [Member]
Number of loans	1	3
Pre-modification outstanding recorded balance	$ 193,437	$ 540,550
Post-modification outstanding recorded balance	193,437	444,645
Commercial Portfolio Segment [Member] | Interest Rate [Member]
Post-modification outstanding recorded balance	0	0
Commercial Portfolio Segment [Member] | Term [Member]
Post-modification outstanding recorded balance	193,437	30,130
Commercial Portfolio Segment [Member] | Combination [Member]
Post-modification outstanding recorded balance		$ 414,515
Consumer and Other Loans [Member]
Number of loans	0	0
Pre-modification outstanding recorded balance
Post-modification outstanding recorded balance
Consumer and Other Loans [Member] | Interest Rate [Member]
Post-modification outstanding recorded balance	0	0
Consumer and Other Loans [Member] | Term [Member]
Post-modification outstanding recorded balance	0
Consumer and Other Loans [Member] | Combination [Member]
Post-modification outstanding recorded balance	$ 0	$ 0