Note 15 - Fair Values of Financial Instruments - Assets Measured at Fair Value on a Non-recurring Basis (Details) - Fair Value, Nonrecurring [Member] - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Other real estate owned	$ 88,000	$ 160,000
Total	88,000	160,000
Fair Value, Inputs, Level 1 [Member]
Other real estate owned
Total
Fair Value, Inputs, Level 2 [Member]
Other real estate owned
Total
Fair Value, Inputs, Level 3 [Member]
Other real estate owned	88,000	160,000
Total	$ 88,000	$ 160,000