Note 4 - Premises and Equipment, Net - Summary of Premises and Equipment (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Property, plant and equipment, gross	$ 92,738,000	$ 94,169,000
Less: accumulated depreciation	34,488,000	35,210,000
Premises and equipment, net	58,250,000	58,959,000
Land and Land Improvements [Member]
Property, plant and equipment, gross	14,553,000	16,533,000
Building [Member]
Property, plant and equipment, gross	55,718,000	56,114,000
Furniture and Fixtures [Member]
Property, plant and equipment, gross	$ 22,467,000	$ 21,522,000