Note 4 - Fair Value of Financial Instruments Fair Value, Measurement Inputs Disclosure (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
Corporate collateralized debt obligations (CDO's)[Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	$ (2,457,000)
Non Corporate Collateralized Debt Obligations And Other Derivative Transactions [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	(193,301,000)
Base Correlation Model Valuation Technique [Member] | Corporate collateralized debt obligations (CDO's)[Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	(2,500,000)	[1]	(1,400,000)	[1]
Base Correlation Model Valuation Technique [Member] | Maximum [Member] | Corporate collateralized debt obligations (CDO's)[Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	3.80%	[2]	4.30%	[2]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Average Credit Spread	0.90%		0.90%
Base Correlation Model Valuation Technique [Member] | Minimum [Member] | Corporate collateralized debt obligations (CDO's)[Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	0.90%	[2]	0.80%	[2]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Average Credit Spread	0.10%		0.10%
Base Correlation Model Valuation Technique [Member] | Weighted Average [Member] | Corporate collateralized debt obligations (CDO's)[Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Correlation Factor	85.00%		85.00%
Discounted Cash Flow Valuation Technique [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investments, Fair Value Disclosure	19,100,000	[1]	18,700,000	[1]
Discounted Cash Flow Valuation Technique [Member] | Other investments | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investments, Fair Value Disclosure	81,600,000	[1]	81,000,000	[1]
Discounted Cash Flow Valuation Technique [Member] | Collateralized Debt Obligation of Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	(56,300,000)	[1]	(67,800,000)	[1]
Discounted Cash Flow Valuation Technique [Member] | TruPs Collateralized Debt Obligation [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	(30,200,000)	[1]	(43,900,000)	[1]
Discounted Cash Flow Valuation Technique [Member] | TruPs-Related VIE [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Variable Interest Entity, Consolidated, Fair Value, Net Asset (Liability)	(47,800,000)	[1]	(68,400,000)	[1]
Discounted Cash Flow Valuation Technique [Member] | NIMS VIEs [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Variable Interest Entity, Consolidated, Fair Value, Net Asset (Liability)	(3,100,000)	[1]	(2,800,000)	[1]
Discounted Cash Flow Valuation Technique [Member] | Maximum [Member] | Collateralized Debt Obligation of Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	3.80%	[2]	4.30%	[2]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Correlation Factor Related to Vintage and Credit Rating	85.00%		85.00%
Discounted Cash Flow Valuation Technique [Member] | Maximum [Member] | TruPs Collateralized Debt Obligation [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	3.80%	[2]	4.30%	[2]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Probability of Paying a Conditional Liquidity Claim	10.00%		12.40%
Discounted Cash Flow Valuation Technique [Member] | Minimum [Member] | Collateralized Debt Obligation of Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	0.90%	[2]	0.80%	[2]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Correlation Factor Related to Vintage and Credit Rating	72.00%		72.00%
Discounted Cash Flow Valuation Technique [Member] | Minimum [Member] | TruPs Collateralized Debt Obligation [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	0.90%	[2]	0.80%	[2]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Probability of Paying a Conditional Liquidity Claim	0.20%		1.10%
Discounted Cash Flow Valuation Technique [Member] | Weighted Average [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Discount Rate	12.30%		12.30%
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Expected Loss Rate	11.10%		11.10%
Discounted Cash Flow Valuation Technique [Member] | Weighted Average [Member] | Other investments | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Discount Rate	1.00%		1.20%
Discounted Cash Flow Valuation Technique [Member] | Weighted Average [Member] | TruPs Collateralized Debt Obligation [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Principal Recovery Rate	75.00%		75.00%
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Principal Recovery Rate Using Distressed Pricing Scenario	65.00%		65.00%
Discounted Cash Flow Valuation Technique [Member] | Weighted Average [Member] | TruPs-Related VIE [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Discount Rate	8.80%		13.10%
Discounted Cash Flow Valuation Technique [Member] | Weighted Average [Member] | NIMS VIEs [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	7.20%	[2]	7.90%	[2]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, NIMS Spread	43.20%		43.80%
Risk-Based Model Valuation Technique [Member] | Non Corporate Collateralized Debt Obligations And Other Derivative Transactions [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	$ (115,300,000)	[1]	$ (119,400,000)	[1]
Risk-Based Model Valuation Technique [Member] | Maximum [Member] | Non Corporate Collateralized Debt Obligations And Other Derivative Transactions [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	3.80%	[2]	4.30%	[2]
Derivative, Expected Remaining Life	20 years		20 years
Risk-Based Model Valuation Technique [Member] | Minimum [Member] | Non Corporate Collateralized Debt Obligations And Other Derivative Transactions [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	0.90%	[2]	0.80%	[2]
Risk-Based Model Valuation Technique [Member] | Less Than [Member] | Minimum [Member] | Non Corporate Collateralized Debt Obligations And Other Derivative Transactions [Member] | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Derivative, Expected Remaining Life	1 year		1 year

[1] Excludes certain assets and liabilities for which we do not develop quantitative unobservable inputs. The fair value estimates for these assets and liabilities are developed using third-party pricing information, generally without adjustment.

[2] Represents the range of our CDS spread that a typical market participant might use in the valuation analysis based on the remaining term of the investment.