Note 9 - Accumulated Other Comprehensive Income (Loss) - Significant Amounts Reclassified Out of Each Component of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Provision for income taxes	$ 395		$ 266		$ 837	$ 508
Total reclassifications for the period	1,934	$ 2,174	1,294	$ 1,190	4,108	2,484
Reclassification out of Accumulated Other Comprehensive Income [Member]
Total reclassifications for the period	(3)		(440)		(23)	(502)
Reclassification out of Accumulated Other Comprehensive Income [Member] | AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Unrealized gains and losses on available-for-sale securities	(4)		(557)		(29)	(635)
Provision for income taxes	$ 1		$ 117		$ 6	$ 133