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						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Provision for income taxes	$ 657			$ 734			$ 1,746	$ 1,571
Total reclassifications for the period	3,040	$ 2,237	$ 2,436	3,375	$ 1,934	$ 2,174	7,713	7,483
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	181			(170)			274	(201)
Provision for income taxes	(38)			36			(58)	43
Total reclassifications for the period							$ 217	$ (158)
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	$ 143			$ (134)