Note 6 - Investment Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Note 6 - Investment Securities (Details) [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	$ 1,787	$ 3,004
Available-for-sale Securities	608,510	626,388
Single Issuer Corporate Debt Security [Member]
Note 6 - Investment Securities (Details) [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	854	$ 354
Available-for-sale Securities	$ 5,000