Note 18 - Stockholders' Equity - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Beginning balance, loss, net of tax	$ 2,602,671	$ 2,431,532	$ 2,474,040	$ 2,446,251
Total other comprehensive (loss)/income, net of tax	(24,484)	(41,546)	(21,238)	(109,809)
Ending balance, loss, net of tax	2,638,736	2,419,559	2,638,736	2,419,559
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member]
Beginning balance, loss, net of tax	(100,704)	(72,210)	(104,832)	211
Net unrealized (losses)/gains arising during the period, pre-tax	(34,133)	(61,316)	(28,272)	(164,128)
Net unrealized (losses)/gains arising during the period, tax	(10,090)	(18,125)	(8,357)	(48,516)
Net unrealized (losses)/gains arising during the period, net of tax	(24,043)	(43,191)	(19,915)	(115,612)
Reclassification adjustment for net losses/(gains) included in net income, pre-tax	34,133	61,316	28,272	164,128
Reclassification adjustment for net losses/(gains) included in net income, tax	10,090	18,125	8,357	48,516
Reclassification adjustment for net losses/(gains) included in net income, net of tax	24,043	43,191	19,915	115,612
Total other comprehensive (loss)/income, pre-tax
Total other comprehensive (loss)/income, tax
Total other comprehensive (loss)/income, net of tax	(124,747)	(115,401)	(124,747)	(115,401)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Beginning balance, loss, net of tax	1,655	882	2,537	(3,276)
Net unrealized (losses)/gains arising during the period, pre-tax	(626)	2,677	(1,878)	11,060
Net unrealized (losses)/gains arising during the period, tax	(185)	791	(555)	3,269
Net unrealized (losses)/gains arising during the period, net of tax	(441)	1,886	(1,323)	7,791
Reclassification adjustment for net losses/(gains) included in net income, pre-tax	0	342	0	2,822
Reclassification adjustment for net losses/(gains) included in net income, tax	0	101	0	834
Reclassification adjustment for net losses/(gains) included in net income, net of tax	0	241	0	1,988
Total other comprehensive (loss)/income, pre-tax	(626)	2,335	(1,878)	8,238
Total other comprehensive (loss)/income, tax	(185)	690	(555)	2,435
Total other comprehensive (loss)/income, net of tax	(441)	1,645	(1,323)	5,803
Ending balance, loss, net of tax	1,214	2,527	1,214	2,527
AOCI Attributable to Parent [Member]
Beginning balance, loss, net of tax	(99,049)	(71,328)	(102,295)	(3,065)
Net unrealized (losses)/gains arising during the period, pre-tax	(34,759)	(58,639)	(30,150)	(153,068)
Net unrealized (losses)/gains arising during the period, tax	(10,275)	(17,334)	(8,912)	(45,247)
Net unrealized (losses)/gains arising during the period, net of tax	(24,484)	(41,305)	(21,238)	(107,821)
Reclassification adjustment for net losses/(gains) included in net income, pre-tax	0	342	0	2,822
Reclassification adjustment for net losses/(gains) included in net income, tax	0	101	0	834
Reclassification adjustment for net losses/(gains) included in net income, net of tax	0	241	0	1,988
Total other comprehensive (loss)/income, pre-tax	(34,759)	(58,981)	(30,150)	(155,890)
Total other comprehensive (loss)/income, tax	(10,275)	(17,435)	(8,912)	(46,081)
Total other comprehensive (loss)/income, net of tax	(24,484)	(41,546)	(21,238)	(109,809)
Ending balance, loss, net of tax	$ (123,533)	$ (112,874)	$ (123,533)	$ (112,874)