Note 18 - Parent Company Financial Information (Details) - Condensed Balance Sheet - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets
Cash and cash equivalents	$ 16,331	$ 10,721	$ 16,991	$ 18,245
Investment securities available-for-sale	379,545	390,475
Other assets	3,265	2,277
Total assets	1,152,337	1,063,141
Liabilities
Other liabilities	3,679	3,224
Shareholders' equity	98,570	93,567	90,443	86,354
Total liabilities and shareholders' equity	1,152,337	1,063,141
Parent Company [Member]
Assets
Cash and cash equivalents	4,667	60	$ 79	$ 48
Investment securities available-for-sale	4,975	8,503
Investment in subsidiary	89,258	85,102
Other assets	74	3
Total assets	98,974	93,668
Liabilities
Other liabilities	404	101
Shareholders' equity	98,570	93,567
Total liabilities and shareholders' equity	$ 98,974	$ 93,668