Note 17 - Stockholders' Equity - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Beginning balance, loss, net of tax			$ 1,828,539
Ending balance, loss, net of tax	$ 1,968,699		1,968,699
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Beginning balance, loss, net of tax	1,001	$ 8,539	(1,545)	$ (5,431)
Net unrealized (losses)/gains arising during the period, net of tax	1,060	938	3,338	15,748
Reclassification adjustment for net losses/(gains) included in net income, net of tax	(14)	(981)	254	(1,821)
Total other comprehensive (loss)/income, net of tax	1,046	(43)	3,592	13,927
Ending balance, loss, net of tax	2,047	8,496	2,047	8,496
Net unrealized (losses)/gains arising during the period, pre-tax	1,829	1,618	5,759	27,170
Reclassification adjustment for net losses/(gains) included in net income, pre-tax	(24)	(1,692)	439	(3,141)
Total other comprehensive (loss)/income, pre-tax	1,805	(74)	6,198	24,029
Net unrealized (losses)/gains arising during the period, tax	769	680	2,421	11,422
Reclassification adjustment for net losses/(gains) included in net income, tax	(10)	(711)	185	(1,320)
Total other comprehensive (loss)/income, tax	759	(31)	2,606	10,102
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Beginning balance, loss, net of tax	(2,421)	(7,397)	(2,170)	(2,995)
Net unrealized (losses)/gains arising during the period, net of tax	157	804	(94)	(3,598)
Reclassification adjustment for net losses/(gains) included in net income, net of tax
Total other comprehensive (loss)/income, net of tax	157	804	(94)	(3,598)
Ending balance, loss, net of tax	(2,264)	(6,593)	(2,264)	(6,593)
Net unrealized (losses)/gains arising during the period, pre-tax	271	1,387	(162)	(6,208)
Reclassification adjustment for net losses/(gains) included in net income, pre-tax
Total other comprehensive (loss)/income, pre-tax	271	1,387	(162)	(6,208)
Net unrealized (losses)/gains arising during the period, tax	114	583	(68)	(2,610)
Reclassification adjustment for net losses/(gains) included in net income, tax
Total other comprehensive (loss)/income, tax	114	583	(68)	(2,610)
AOCI Attributable to Parent [Member]
Beginning balance, loss, net of tax	(1,420)	1,142	(3,715)	(8,426)
Net unrealized (losses)/gains arising during the period, net of tax	1,217	1,742	3,244	12,150
Reclassification adjustment for net losses/(gains) included in net income, net of tax	(14)	(981)	254	(1,821)
Total other comprehensive (loss)/income, net of tax	1,203	761	3,498	10,329
Ending balance, loss, net of tax	(217)	1,903	(217)	1,903
Net unrealized (losses)/gains arising during the period, pre-tax	2,100	3,005	5,597	20,962
Reclassification adjustment for net losses/(gains) included in net income, pre-tax	(24)	(1,692)	439	(3,141)
Total other comprehensive (loss)/income, pre-tax	2,076	1,313	6,036	17,821
Net unrealized (losses)/gains arising during the period, tax	883	1,263	2,353	8,812
Reclassification adjustment for net losses/(gains) included in net income, tax	(10)	(711)	185	(1,320)
Total other comprehensive (loss)/income, tax	$ 873	$ 552	$ 2,538	$ 7,492