Note 4 - Premises and Equipment, Net - Summary of Premises and Equipment (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Property, plant and equipment, gross	$ 75,220,000	$ 74,171,000
Less: accumulated depreciation	29,372,000	28,715,000
Premises and equipment, net	45,848,000	45,456,000
Land and Land Improvements [Member]
Property, plant and equipment, gross	17,665,000	17,285,000
Building [Member]
Property, plant and equipment, gross	39,836,000	39,691,000
Furniture and Fixtures [Member]
Property, plant and equipment, gross	$ 17,719,000	$ 17,195,000