Note 10 - Accumulated Other Comprehensive Income - Unrealized Gains (Losses) of Accumulated Other Comprehensive Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net unrealized loss during the period, before tax	$ (1,055)
Net unrealized loss during the period, tax	273
Unrealized loss on available-for-sale securities, net of tax	(782)
Other comprehensive income loss, before tax	(1,055)
Other comprehensive income loss, tax	273
Other comprehensive income loss, net of tax	$ (782)