Note 7 - Core Deposit Intangible Assets, Net (Details Textual) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Core Deposits, Gross	$ 17,500,000	$ 17,500,000
Finite-Lived Intangible Assets, Accumulated Amortization	11,900,000	9,900,000
Finite-Lived Intangible Assets, Net, Ending Balance	$ 5,561,000	$ 7,600,000