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, 2021	Dec. 31, 2020
Total	$ 524,000	$ 407,000
Other real estate owned	0	9,000
Fair Value, Inputs, Level 1 [Member]
Total	0	0
Other real estate owned		0
Fair Value, Inputs, Level 2 [Member]
Total	0	0
Other real estate owned		0
Fair Value, Inputs, Level 3 [Member]
Total	524,000	407,000
Other real estate owned		9,000
Commercial Portfolio Segment [Member]
Impaired loans	54,000	58,000
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 1 [Member]
Impaired loans	0	0
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 2 [Member]
Impaired loans	0	0
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Impaired loans	54,000	58,000
Commercial Real Estate Portfolio Segment [Member]
Impaired loans	470,000	340,000
Commercial Real Estate Portfolio Segment [Member] | Fair Value, Inputs, Level 1 [Member]
Impaired loans	0	0
Commercial Real Estate Portfolio Segment [Member] | Fair Value, Inputs, Level 2 [Member]
Impaired loans	0	0
Commercial Real Estate Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Impaired loans	$ 470,000	$ 340,000