Note 16 - Stockholders' Equity - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Ending balance, loss, net of tax	$ 1,897,766		$ 1,897,766
Beginning balance, loss, net of tax			1,828,539
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Reclassification adjustment for net losses/(gains) included in net income, net of tax	(2)	$ (959)	268	$ (840)
Total other comprehensive (loss)/income, net of tax	2,772	3,497	2,546	13,970
Total other comprehensive (loss)/income, pre-tax	4,783	6,033	4,393	24,103
Total other comprehensive (loss)/income, tax	2,011	2,536	1,847	10,133
Total other comprehensive (loss)/income, net of tax	2,772	3,497	2,546	13,970
Ending balance, loss, net of tax	1,001	8,539	1,001	8,539
Beginning balance, loss, net of tax	(1,771)	5,042	(1,545)	(5,431)
Net unrealized (losses)/gains arising during the period, pre-tax	4,786	7,688	3,930	25,552
Net unrealized (losses)/gains arising during the period, tax	2,012	3,232	1,652	10,742
Net unrealized (losses)/gains arising during the period, net of tax	2,774	4,456	2,278	14,810
Reclassification adjustment for net losses/(gains) included in net income, pre-tax	(3)	(1,655)	463	(1,449)
Reclassification adjustment for net losses/(gains) included in net income, tax	(1)	(696)	195	(609)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Reclassification adjustment for net losses/(gains) included in net income, net of tax
Total other comprehensive (loss)/income, net of tax	(550)	(1,282)	(251)	(4,402)
Total other comprehensive (loss)/income, pre-tax	(949)	(2,212)	(433)	(7,595)
Total other comprehensive (loss)/income, tax	(399)	(930)	(182)	(3,193)
Total other comprehensive (loss)/income, net of tax	(550)	(1,282)	(251)	(4,402)
Ending balance, loss, net of tax	(2,421)	(7,397)	(2,421)	(7,397)
Beginning balance, loss, net of tax	(1,871)	(6,115)	(2,170)	(2,995)
Net unrealized (losses)/gains arising during the period, pre-tax	(949)	(2,212)	(433)	(7,595)
Net unrealized (losses)/gains arising during the period, tax	(399)	(930)	(182)	(3,193)
Net unrealized (losses)/gains arising during the period, net of tax	(550)	(1,282)	(251)	(4,402)
Reclassification adjustment for net losses/(gains) included in net income, pre-tax
Reclassification adjustment for net losses/(gains) included in net income, tax
AOCI Attributable to Parent [Member]
Reclassification adjustment for net losses/(gains) included in net income, net of tax	(2)	(959)	268	(840)
Total other comprehensive (loss)/income, net of tax	2,222	2,215	2,295	9,568
Total other comprehensive (loss)/income, pre-tax	3,834	3,821	3,960	16,508
Total other comprehensive (loss)/income, tax	1,612	1,606	1,665	6,940
Total other comprehensive (loss)/income, net of tax	2,222	2,215	2,295	9,568
Ending balance, loss, net of tax	(1,420)	1,142	(1,420)	1,142
Beginning balance, loss, net of tax	(3,642)	(1,073)	(3,715)	(8,426)
Net unrealized (losses)/gains arising during the period, pre-tax	3,837	5,476	3,497	17,957
Net unrealized (losses)/gains arising during the period, tax	1,613	2,302	1,470	7,549
Net unrealized (losses)/gains arising during the period, net of tax	2,224	3,174	2,027	10,408
Reclassification adjustment for net losses/(gains) included in net income, pre-tax	(3)	(1,655)	463	(1,449)
Reclassification adjustment for net losses/(gains) included in net income, tax	$ (1)	$ (696)	$ 195	$ (609)