Note 4 - Premises and Equipment, Net - Summary of Premises and Equipment (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Property, plant and equipment, gross	$ 94,253,000	$ 94,169,000
Less: accumulated depreciation	36,955,000	35,210,000
Total premises and equipment	57,298,000	58,959,000
Land and Land Improvements [Member]
Property, plant and equipment, gross	15,111,000	16,533,000
Building [Member]
Property, plant and equipment, gross	56,168,000	56,114,000
Furniture and Fixtures [Member]
Property, plant and equipment, gross	$ 22,974,000	$ 21,522,000