Note 6 - Investments Investments Trading Securities (Details) (USD $)	3 Months Ended		6 Months Ended			6 Months Ended	12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2014 Securities (Assets)	Dec. 31, 2013 Securities (Assets)	Jun. 30, 2014 US government and agency securities	Dec. 31, 2013 US government and agency securities	Jun. 30, 2014 State and municipal obligations	Dec. 31, 2013 State and municipal obligations	Jun. 30, 2014 Corporate bonds and notes	Dec. 31, 2013 Corporate bonds and notes	Jun. 30, 2014 RMBS	Dec. 31, 2013 RMBS	Jun. 30, 2014 CMBS	Dec. 31, 2013 CMBS	Jun. 30, 2014 Other ABS	Dec. 31, 2013 Other ABS	Jun. 30, 2014 Foreign government securities	Dec. 31, 2013 Foreign government securities	Jun. 30, 2014 Equity securities	Dec. 31, 2013 Equity securities	Jun. 30, 2014 Other investments	Dec. 31, 2013 Other investments	Aug. 31, 2013 2013 Freddie Mac Agreement [Member] Mortgage Insurance Segment	Jun. 30, 2014 First Lien Position [Member] 2013 Freddie Mac Agreement [Member] Primary Mortgage Product [Member] Mortgage Insurance Segment	Dec. 31, 2013 First Lien Position [Member] 2013 Freddie Mac Agreement [Member] Primary Mortgage Product [Member] Mortgage Insurance Segment	Jun. 30, 2014 Portugal, Ireland, Italy, Greece, Spain and Hungary Government Securities [Member] Foreign government securities country	Dec. 31, 2013 Portugal, Ireland, Italy, Greece, Spain and Hungary Government Securities [Member] Foreign government securities country	Jun. 30, 2014 Non European Countries Outside U.S. Under Economic Stress [Member] Foreign government securities	Dec. 31, 2013 Non European Countries Outside U.S. Under Economic Stress [Member] Foreign government securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	$ 2,691,077,000		$ 2,691,077,000		$ 3,117,429,000			$ 318,407,000	$ 393,815,000	$ 607,961,000	$ 595,070,000	$ 977,168,000	$ 1,024,574,000	$ 235,216,000	$ 487,239,000	$ 278,582,000	$ 288,895,000	$ 155,551,000	$ 195,816,000	$ 29,153,000	$ 40,657,000	$ 88,365,000	$ 90,604,000	$ 674,000	$ 759,000
Trading Securities, Unrealized Holding Gain	47,447,000	(138,658,000)	115,528,000	(156,441,000)		97,000,000	(140,900,000)
Restricted Investments Held as Collateral for Master Transaction Agreement, Net																										205,000,000	209,000,000	205,000,000
Investment Portfolio	$ 4,947,745,000		$ 4,947,745,000		$ 4,931,157,000																								$ 0	$ 0	$ 0	$ 0
Number Of Stressed European Countries																													6	6