Note 19 - Stockholders' Equity - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Beginning balance, loss, net of tax		$ 2,121,866	$ 1,973,304
Total other comprehensive (loss)/income, net of tax		7,575	(9,324)
Ending balance, loss, net of tax		2,163,329	2,009,792
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Beginning balance, loss, net of tax		(17,765)	(1,060)
Reclassification adjustment for stranded tax effects of Tax Cuts and Jobs Act, tax	[1]		200
Reclassification adjustment for stranded tax effects of Tax Cuts and Jobs Act, net of tax	[1]		(200)
Net unrealized (losses)/gains arising during the period, pre-tax		12,491	(16,346)
Net unrealized (losses)/gains arising during the period, tax		3,692	(4,832)
Net unrealized (losses)/gains arising during the period, net of tax		8,799	(11,514)
Total other comprehensive (loss)/income, pre-tax		12,491	(16,346)
Total other comprehensive (loss)/income, tax		3,692	(4,832)
Total other comprehensive (loss)/income, net of tax		8,799	(11,514)
Ending balance, loss, net of tax		(8,966)	(21,333)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Beginning balance, loss, net of tax		(241)	(1,451)
Reclassification adjustment for stranded tax effects of Tax Cuts and Jobs Act, tax	[1]		315
Reclassification adjustment for stranded tax effects of Tax Cuts and Jobs Act, net of tax	[1]		(315)
Net unrealized (losses)/gains arising during the period, pre-tax		(1,738)	3,113
Net unrealized (losses)/gains arising during the period, tax		(514)	920
Net unrealized (losses)/gains arising during the period, net of tax		(1,224)	2,193
Total other comprehensive (loss)/income, pre-tax		(1,738)	3,113
Total other comprehensive (loss)/income, tax		(514)	920
Total other comprehensive (loss)/income, net of tax		(1,224)	2,193
Ending balance, loss, net of tax		(1,465)	427
AOCI Attributable to Parent [Member]
Beginning balance, loss, net of tax		(18,006)	(2,511)
Reclassification adjustment for stranded tax effects of Tax Cuts and Jobs Act, tax	[1]		515
Reclassification adjustment for stranded tax effects of Tax Cuts and Jobs Act, net of tax	[1]		(515)
Reclassification adjustment for equity securities, pre-tax	[2]		(12,151)
Reclassification adjustment for equity securities, tax	[2]		(3,592)
Reclassification adjustment for equity securities, net of tax	[2]		(8,559)
Net unrealized (losses)/gains arising during the period, pre-tax		10,753	(13,233)
Net unrealized (losses)/gains arising during the period, tax		3,178	(3,912)
Net unrealized (losses)/gains arising during the period, net of tax		7,575	(9,321)
Total other comprehensive (loss)/income, pre-tax		10,753	(13,233)
Total other comprehensive (loss)/income, tax		3,178	(3,912)
Total other comprehensive (loss)/income, net of tax		7,575	(9,321)
Ending balance, loss, net of tax		$ (10,431)	$ (20,906)

[1] These amounts were recorded as of January 1, 2018 as a result of the adoption of ASU 2018-2.

[2] This amount was recorded as of January 1, 2018 as a result of the adoption of ASU 2016-1.