Note 4 - Premises and Equipment, Net - Summary of Premises and Equipment (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Property, plant and equipment, gross	$ 87,022,000	$ 81,699,000
Less: accumulated depreciation	35,199,000	33,378,000
Premises and equipment, net	51,823,000	48,321,000
Land and Land Improvements [Member]
Property, plant and equipment, gross	18,140,000	18,198,000
Building [Member]
Property, plant and equipment, gross	49,120,000	45,362,000
Furniture and Fixtures [Member]
Property, plant and equipment, gross	$ 19,762,000	$ 18,139,000