Note 1 - Summary of Accounting Policies - Premises and Equipment Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2019
Building [Member]
Property, plant, and equipment, useful life (Year)	31 years 182 days
Equipment [Member] | Minimum [Member]
Property, plant, and equipment, useful life (Year)	3 years
Equipment [Member] | Maximum [Member]
Property, plant, and equipment, useful life (Year)	12 years
Furniture and Fixtures [Member] | Minimum [Member]
Property, plant, and equipment, useful life (Year)	3 years
Furniture and Fixtures [Member] | Maximum [Member]
Property, plant, and equipment, useful life (Year)	7 years
Leasehold Improvements [Member] | Minimum [Member]
Property, plant, and equipment, useful life (Year)	5 years
Leasehold Improvements [Member] | Maximum [Member]
Property, plant, and equipment, useful life (Year)	15 years
Automobiles [Member] | Minimum [Member]
Property, plant, and equipment, useful life (Year)	3 years
Automobiles [Member] | Maximum [Member]
Property, plant, and equipment, useful life (Year)	5 years