Note 6 - Accumulated Other Comprehensive Income - Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Balance		$ 146,044	$ 140,695	$ 143,810	$ 137,775
Other comprehensive income (loss)	[1]				2,235
Balance		146,055	142,056	146,055	142,056
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	[1]	3,893	3,761	4,284	1,842
Other comprehensive income (loss)	[1]	(283)	316	(674)
Balance	[1]	$ 3,610	$ 4,077	$ 3,610	$ 4,077

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