Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($)	1 Months Ended	12 Months Ended
	Apr. 30, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Maturity Period of Interest-bearing Deposits in Other Banks (Year)		1 year
Debt Securities, Held-to-maturity, Total		$ 0
Minimum Period of Time Between Issuance and Sale of Loan Commitment (Day)		30 days
Maximum Period of Time Between Issuance and Sale of Loan Commitment (Day)		60 days
Period to Discontinued Interest Accrual on Delinquent Loans (Day)		90 days
Past Due Period when Loans are Charged Off (Day)		120 days
Financing Receivable, Troubled Debt Restructuring		$ 1,725,000	$ 1,976,000
Finite-Lived Intangible Asset, Useful Life (Year)	120 months
Marketing and Advertising Expense, Total		506,000	453,000	$ 473,000
Financing Receivable, Paycheck Protection Program Loans Originated Through the CARES Act		$ 12,200,000	211,300,000
Financing Receivable, Loans Modified During Period			$ 30,000,000.0
Software Development [Member]
Property, Plant and Equipment, Useful Life (Year)		3 years
Minimum [Member]
Property, Plant and Equipment, Useful Life (Year)		3 years
Finite-Lived Intangible Asset, Useful Life (Year)		5 years
Maximum [Member]
Property, Plant and Equipment, Useful Life (Year)		39 years
Finite-Lived Intangible Asset, Useful Life (Year)		10 years