Note 4 - Premises and Equipment, Net - Summary of Premises and Equipment (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Property, plant and equipment, gross	$ 94,557,000	$ 94,253,000
Less: accumulated depreciation	38,479,000	36,955,000
Premises and equipment, net	56,078,000	57,298,000
Land and Land Improvements [Member]
Property, plant and equipment, gross	15,111,000	15,111,000
Building [Member]
Property, plant and equipment, gross	56,202,000	56,168,000
Furniture and Fixtures [Member]
Property, plant and equipment, gross	$ 23,244,000	$ 22,974,000