Note 7 - Investments Investments Trading Securities (Details) (USD $)	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	$ 4,211,059,000		$ 4,562,821,000
Trading Securities, Change in Unrealized Holding Gain (Loss)	126,539,000		78,637,000		56,352,000
Securities (Assets)
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities, Change in Unrealized Holding Gain (Loss)	112,100,000		27,000,000
US government and agency securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	710,006,000		703,636,000
State and municipal obligations
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	964,748,000		983,680,000
Corporate bonds and notes
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	683,864,000		1,034,206,000
RMBS
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	928,887,000		953,416,000
CMBS
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	224,180,000		193,244,000
CDO
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	5,467,000		2,406,000
Other ABS
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	98,729,000		132,149,000
Foreign government securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	102,851,000	[1]	83,508,000	[1]
Portugal, Ireland, Italy, Greece and Spain Government Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	0
Number Of Stressed Eurozone Countries	5
Italian Government Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities			15,500,000
German foreign government securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	42,600,000
Japanese foreign government securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	28,000,000
Convertible Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	346,338,000		318,940,000
Equity securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	140,764,000		155,636,000
Other investments
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	$ 5,225,000		$ 2,000,000

[1] As of December 31, 2011, nearly all of our foreign government securities were rated A or higher by a Nationally Recognized Statistical Rating Organization ("NRSRO"). As of December 31, 2011, our trading portfolio included no securities of five Eurozone countries (Portugal, Ireland, Italy, Greece and Spain, collectively, the "Stressed Eurozone Countries"), whose sovereign obligations have been under stress due to economic uncertainty, potential restructuring and ratings downgrades, or securities of any other countries under similar stress. As of December 31, 2010, our trading portfolio exposure to the Stressed Eurozone Countries consisted of $15.5 million of Italian securities. Our largest concentrations of foreign government securities as of December 31, 2011, were Germany ($42.6 million fair value) and Japan ($28.0 million fair value).