Note 8 - Deposits - Interest Expense on Deposits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
NOW, Interest expense	$ 15	$ 7	$ 8
NOW, Weighted Avg. Effective Interest Rate	0.06%	0.0272%	0.0293%
Savings, Interest expense	$ 995	$ 1,160	$ 778
Savings, Weighted Avg. Effective Interest Rate	0.8493%	0.8069%	0.6196%
Money market, Interest expense	$ 549	$ 5	$ 7
Money market, Weighted Avg. Effective Interest Rate	1.3446%	0.0367%	0.0365%
Certificates of deposit, less than $250,000, Interest expense	$ 3,048	$ 1,875	$ 888
Certificates of deposit, less than $250,000, Weighted Avg. Effective Interest Rate	1.5735%	1.0499%	0.646%
Certificates of deposit, $250,000 or greater, Interest expense	$ 1,226	$ 912	$ 215
Certificates of deposit, $250,000 or greater, Weighted Avg. Effective Interest Rate	1.6846%	1.4577%	0.9722%
Brokered deposits, Interest expense	$ 3,191	$ 989	$ 346
Brokered deposits, Weighted Avg. Effective Interest Rate	1.9109%	1.2417%	0.2579%
Interest Expense on Deposits, Total, Interest expense	$ 9,024	$ 4,948	$ 2,242
Interest Expense on Deposits, Total, Weighted Avg. Effective Interest Rate	1.4648%	0.9878%	0.5533%