Note 7 - Investments Investments Trading Securities (Details) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	$ 4,094,622,000		$ 4,211,059,000
Portugal, Ireland, Italy, Greece, Spain and Hungary Government Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities			0
Number Of Stressed European Countries			6
Securities (Assets)
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities, Unrealized Holding Gain	29,800,000		112,100,000
US government and agency securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	428,519,000		710,006,000
State and municipal obligations
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	669,975,000		964,748,000
Corporate bonds and notes
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	1,357,175,000		683,864,000
RMBS
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	663,307,000		928,887,000
CMBS
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	237,294,000		224,180,000
CDO
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	0		5,467,000
Other ABS
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	254,102,000		98,729,000
Foreign government securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	117,686,000	[1]	102,851,000	[1]
German foreign government securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	22,100,000		42,600,000
Japanese foreign government securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	56,400,000		28,000,000
Convertible Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	211,944,000		346,338,000
Equity securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	153,722,000		140,764,000
Other investments
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	$ 898,000		$ 5,225,000

[1] Our largest concentrations of foreign government securities as of December 31, 2012 and 2011 were Japan ($56.4 million and $28.0 million fair value, respectively) and Germany ($22.1 million and $42.6 million fair value, respectively). As of December 31, 2012 and 2011, nearly all of our foreign government securities were rated A or higher by a nationally recognized statistical rating organization. As of December 31, 2012 and 2011, our trading portfolio included no foreign sovereign or sub-sovereign securities of the six European countries (Portugal, Ireland, Italy, Greece, Spain and Hungary) whose sovereign and sub-sovereign obligations have been under particular stress due to economic uncertainty, potential restructuring and ratings downgrades or securities of any other countries under similar stress.