Note 13 - Condensed Financial Statements of Parent Company - Condensed Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income
Realized securities gains, net	$ 14	$ 232	$ 33
Other income	1,148	1,289	1,295
Expenses
Income before income tax benefit and equity in undistributed net income of subsidiaries	20,385	18,894	20,573
Applicable income tax benefit	6,293	3,952	4,740
Net income	14,092	14,942	15,833
Parent Company [Member]
Income
Dividends from subsidiaries	8,141	9,421	7,930
Interest on securities – taxable		2	3
Realized securities gains, net	4
Other income	1,018	987	1,208
Total income	9,163	10,410	9,141
Expenses
Other expenses	1,986	1,992	2,051
Income before income tax benefit and equity in undistributed net income of subsidiaries	7,177	8,418	7,090
Applicable income tax benefit	383	628	210
Income before equity in undistributed net income of subsidiaries	7,560	9,046	7,300
Equity in undistributed net income of subsidiaries	6,532	5,896	8,533
Net income	$ 14,092	$ 14,942	$ 15,833