Note 6 - Investments Investments Trading Securities (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	$ 2,728,976,000	$ 3,117,429,000
Investment Portfolio	4,858,579,000	4,931,157,000
Securities (Assets)
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities, Unrealized Holding Gain	58,900,000	(140,900,000)
US government and agency securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	333,804,000	393,815,000
State and municipal obligations
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	611,410,000	595,070,000
Corporate bonds and notes
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	967,207,000	1,024,574,000
RMBS
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	245,232,000	487,239,000
CMBS
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	282,561,000	288,895,000
Other ABS
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	170,289,000	195,816,000
Foreign government securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	28,866,000	40,657,000
Equity securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	88,860,000	90,604,000
Other investments
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	747,000	759,000
First Lien Position [Member] | 2013 Freddie Mac Agreement [Member] | Primary Mortgage Product [Member] | Mortgage Insurance Segment
Schedule of Trading Securities and Other Trading Assets [Line Items]
Restricted Investments Held as Collateral for Master Transaction Agreement, Net	208,000,000	205,000,000
Portugal, Ireland, Italy, Greece, Spain and Hungary Government Securities [Member] | Foreign government securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Investment Portfolio	$ 0	$ 0
Number Of Stressed European Countries	6	6