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, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Provision for income taxes	$ 571		$ 395		$ 1,088	$ 837
Total reclassifications for the period	2,237	$ 2,436	1,934	$ 2,174	4,673	4,108
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	103		(4)		93	(29)
Provision for income taxes	(22)		1		(19)	6
Total reclassifications for the period					$ 74	$ (23)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Total reclassifications for the period	$ 81		$ (3)