Note 13 - Stockholders' Equity and Earnings per Share (Details) - Accumulated Other Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Beginning balance, (loss)/income, net of tax
Beginning balance, (loss)/income, net-of-tax	$ (29,729)	$ 465
Net unrealized gains/(losses) arising during the period
Net unrealized gains/(losses) arising during the period, pre-tax	34,941	(117,515)
Net unrealized gains/(losses) arising during the period, tax expense/ (benefit)	14,692	(49,407)
Net unrealized gains/(losses) arising during the period, net-of-tax	20,249	(68,108)
Reclassification adjustment for net gains included in net income
Reclassification adjustment for net gains included in net income, pre-tax	6,748	27,362
Reclassification adjustment for net gains included in net income, tax expense/ (benefit)	2,837	11,503
Reclassification adjustment for net gains included in net income, net-of-tax	3,911	15,859
Net unrealized gains arising from transferring securities held-to-maturity to available-for-sale		38,052
Net unrealized gains arising from transferring securities held-to-maturity to available-for-sale		15,997
Net unrealized gains arising from transferring securities held-to-maturity to available-for-sale		22,055
Total other comprehensive income/(loss)
Total other comprehensive income/(loss), pre-tax	41,689	(52,101)
Total other comprehensive income/(loss), tax expense/ (benefit)	17,529	(21,907)
Total other comprehensive income/(loss), net-of-tax	24,160	(30,194)	9,197
Ending balance, loss, net of tax
Ending balance, loss, net-of-tax	(5,569)	(29,729)	465
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Beginning balance, (loss)/income, net of tax
Beginning balance, (loss)/income, net-of-tax	(29,729)	465
Net unrealized gains/(losses) arising during the period
Net unrealized gains/(losses) arising during the period, pre-tax	39,077	(117,515)
Net unrealized gains/(losses) arising during the period, tax expense/ (benefit)	16,431	(49,407)
Net unrealized gains/(losses) arising during the period, net-of-tax	22,646	(68,108)
Reclassification adjustment for net gains included in net income
Reclassification adjustment for net gains included in net income, pre-tax	6,748	27,362
Reclassification adjustment for net gains included in net income, tax expense/ (benefit)	2,837	11,503
Reclassification adjustment for net gains included in net income, net-of-tax	3,911	15,859
Total other comprehensive income/(loss)
Total other comprehensive income/(loss), pre-tax	45,825	(52,101)
Total other comprehensive income/(loss), tax expense/ (benefit)	19,268	(21,907)
Total other comprehensive income/(loss), net-of-tax	26,557	(30,194)
Ending balance, loss, net of tax
Ending balance, loss, net-of-tax	(3,172)	(29,729)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Net unrealized gains/(losses) arising during the period
Net unrealized gains/(losses) arising during the period, pre-tax	(4,136)
Net unrealized gains/(losses) arising during the period, tax expense/ (benefit)	(1,739)
Net unrealized gains/(losses) arising during the period, net-of-tax	(2,397)
Total other comprehensive income/(loss)
Total other comprehensive income/(loss), pre-tax	(4,136)
Total other comprehensive income/(loss), tax expense/ (benefit)	(1,739)
Total other comprehensive income/(loss), net-of-tax	(2,397)
Ending balance, loss, net of tax
Ending balance, loss, net-of-tax	$ (2,397)