Note 15 - Comprehensive Income - Reclassification out of Accumulated Other Comprehensive (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net gains on sale of investment securities									$ 0	$ 0	$ 195
Income tax benefit	$ 6,213	$ 7,228	$ 7,437	$ 9,077	$ 12,348	$ 10,425	$ 11,889	$ 11,351	29,955	46,013	44,705
Net income	19,273	21,407	21,394	24,929	32,557	28,915	32,358	31,381	87,003	125,211	130,353
Interest income (expense)	$ 67,135	$ 61,329	$ 57,482	$ 49,013	$ 34,460	$ 18,819	$ 9,765	$ 8,583	234,959	71,627	38,860
Salaries and employee benefits									88,325	81,289	64,341
Reclassification out of Accumulated Other Comprehensive Income [Member]
Net income									13,937	2,221	(1,413)
Reclassification out of Accumulated Other Comprehensive Income [Member] | AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member]
Net gains on sale of investment securities									0	0	195
Income tax benefit									0	0	(48)
Net income									0	0	147
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Income tax benefit									(6,086)	(976)	528
Net income									14,144	2,267	(1,345)
Interest income (expense)									20,230	3,243	(1,873)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Income tax benefit									89	20	84
Net income									(207)	(46)	(215)
Salaries and employee benefits									$ (296)	$ (66)	$ (299)