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
	Mar. 31, 2021	Mar. 31, 2020
Provision for income taxes	$ 441	$ 243
Total reclassifications for the period	2,174	1,190
Reclassification out of Accumulated Other Comprehensive Income [Member]
Total reclassifications for the period	(20)	(62)
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	(26)	(78)
Provision for income taxes	$ 6	$ 16