Note 6 - Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Balance		$ 137,775	$ 128,290
Other comprehensive income (loss)		(4,079)	795
Balance		132,687	131,699
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	[1]	1,842	(154)
Other comprehensive income (loss)	[1]	(4,079)	795
Balance	[1]	$ (2,237)	$ 641

[1] All amounts are net of tax. Amounts in parentheses indicate debits to AOCI.