Note 5 - Premises and Equipment, Net - Summary of Premises and Equipment (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Property, plant and equipment, gross	$ 81,699,000	$ 76,623,000
Less: accumulated depreciation	33,378,000	30,589,000
Total premises and equipment	48,321,000	46,034,000
Land and Land Improvements [Member]
Property, plant and equipment, gross	18,198,000	18,046,000
Building [Member]
Property, plant and equipment, gross	45,362,000	41,179,000
Furniture and Fixtures [Member]
Property, plant and equipment, gross	$ 18,139,000	$ 17,398,000