Note 5 - Fair Value of Financial Instruments Fair Value, Option, Quantitative Disclosures (Details) (USD $)																12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 Collateralized Debt Obligations [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2010 Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2011 Consolidated Financial Guaranty Insurance Contracts [Member]		Dec. 31, 2010 Consolidated Financial Guaranty Insurance Contracts [Member]		Dec. 31, 2011 Consolidated Financial Guaranty Insurance Contracts [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2011 NIMS VIEs [Member]		Dec. 31, 2010 NIMS VIEs [Member]		Dec. 31, 2011 NIMS VIEs [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2010 NIMS VIEs [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2011 Consolidated Committed Preferred Custodial Trust Securities [Member]		Dec. 31, 2010 Consolidated Committed Preferred Custodial Trust Securities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Net Par Outstanding Subject To Recapture or Terminatino, Percentage				90.00%
Portion of Percentage of Net Par Outstanding With Option to Terminate That Have Fair Value Caps At Zero				19.00%
Percent of Corporate CDO Deals With Minimum Fair Premium Amount				43.00%
Percent of Aggregate Net Par Outstanding for Non Corporate CDOs Whose Contractual Premiums are Subject to Change Due to Right of Termination				89.00%
Percent of Aggregate Net Par Outstanding Non Corporate CDOs Subject to Termination With Fair Value Cap				26.00%
Net par outstanding on CDO of ABS transaction				$ 450,600,000			$ 580,000,000	[1]	$ 584,600,000	[1]	$ 129,400,000	$ 18,500,000	[2]	$ 135,800,000	[2]	$ 18,000,000	$ 135,600,000	$ 150,000,000	[3]	$ 150,000,000	[3]
Derivative Assets	17,212,000	26,212,000					0		0			1,600,000		10,900,000
VIE debt	228,240,000	520,114,000	296,080,000				218,800,000		379,100,000		103,700,000	9,400,000		141,000,000
Variable Interest Entity Accounts Payable And Other Liabilities	530,000	837,000									300,000
Number Of Consolidated Other Financial Guaranty Transactions					2	2	2				2
Change in Impact of Non Performance Risk on Fair Value of Financial Instruments																$ 10,200,000	$ 6,300,000
Number of Committed Preferred Custodial Trusts																		3

[1] The difference between the carrying amounts of the net asset/liability position and maximum exposure related to VIEs is primarily due to the difference between the face amount of the obligation and the recorded fair values, which include an adjustment for our non-performance risk. The maximum exposure is based on the net par amount of our insured obligations as of the reporting date.

[2] The difference between the carrying amounts of the net asset/liability position and maximum exposure related to VIEs is primarily due to the difference between the face amount of the obligation and the recorded fair values, which includes an adjustment for our non-performance risk. The maximum exposure is based on the net par amount of our insured obligations as of the reporting date.

[3] The maximum exposure is based on our carrying amounts of the investments.