Note 3 - Loans Receivable (Details Textual)	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Impaired Financing Receivable, Interest Income, Cash Basis Method, Total	$ 84,000	$ 99,000	$ 181,000	$ 271,000
Financing Receivable, Number of Temporary Loan Modifications	346		346
Financing Receivable, Temporary Loan Modifications	$ 174,900,000		$ 174,900,000
Financing Receivable, Customers with Deferred Loan Payments, Percentage of Total Loans	16.30%		16.30%
Financing Receivable, Modifications, Number of Contracts	0	0	0	0
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts	0		0
Financing Receivable, Troubled Debt Restructuring, Commitment to Lend	$ 0		$ 0
Financing Receivable, 90 Days or More Past Due, Still Accruing	$ 0		$ 0		$ 0