Note 7 - Comprehensive (Loss) Income - Reclassification out of Accumulated Other Comprehensive (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Net gains on sale of securities available-for-sale	$ 0	$ 0	$ 0	$ 195
Income tax expense	10,425	10,881	33,665	32,404
Net income	28,915	32,097	92,654	97,315
Borrowings	18,819	8,781	37,167	30,281
Other components of net periodic pension expense	(143)	(67)	(429)	(201)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Net income	823	(292)	330	(1,124)
Reclassification out of Accumulated Other Comprehensive Income [Member] | AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member]
Net gains on sale of securities available-for-sale	0	0	0	195
Income tax expense	0	0	0	(48)
Net income	0	0	0	147
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Income tax expense	(343)	90	(159)	434
Net income	835	(238)	365	(1,109)
Borrowings	1,178	(328)	524	(1,543)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Income tax expense	5	21	14	63
Net income	(12)	(54)	(35)	(162)
Other components of net periodic pension expense	$ (17)	$ (75)	$ (49)	$ (225)