Note 5 - Investments Investments Trading Securities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Schedule of Trading Securities and Other Trading Assets [Line Items]
Marketable Securities, Unrealized Gain (Loss)	$ 13,700	$ 65,700
Trading Securities	1,466,435	1,633,584
US government and agency securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	131,335	134,530
State and municipal obligations
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	312,340	343,926
Corporate bonds and notes
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	660,964	708,361
RMBS
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	80,772	89,810
CMBS
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	169,443	188,615
Other ABS
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	30,952	77,755
Foreign government securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	13,548	18,331
Equity securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	$ 67,081	$ 72,256