Note 5 - Premises and Equipment, Net - Summary of Premises and Equipment (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Property, plant and equipment, gross	$ 92,598,000	$ 81,699,000
Less: accumulated depreciation	35,271,000	33,378,000
Total premises and equipment	57,327,000	48,321,000
Land and Land Improvements [Member]
Property, plant and equipment, gross	17,039,000	18,198,000
Building [Member]
Property, plant and equipment, gross	52,847,000	45,362,000
Furniture and Fixtures [Member]
Property, plant and equipment, gross	$ 22,712,000	$ 18,139,000