Note 4 - Fair Value of Financial Instruments Fair Value Measurement Inputs for Level III Assets and Liabilities (Details) (USD $)	Mar. 31, 2012		Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Derivative Assets	$ 16,202,000		$ 17,212,000
Derivative liabilities	202,100,000		126,006,000
VIE debt	255,234,000		228,240,000
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | Collateralized Debt Obligation of Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Derivative Assets	1,600,000	[1]
Derivative liabilities	58,200,000	[1]
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | Collateralized Debt Obligation of Commercial Mortgage Backed Securities [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	11.00%	[2]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Correlation Factor Related to Vintage and Credit Rating	72.00%
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | Collateralized Debt Obligation of Commercial Mortgage Backed Securities [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	21.00%	[2]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Correlation Factor Related to Vintage and Credit Rating	85.00%
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | TruPs Collateralized Debt Obligation [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Derivative Assets	1,400,000	[1]
Derivative liabilities	44,900,000	[1]
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | TruPs Collateralized Debt Obligation [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	11.00%	[2]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Probability of Paying a Conditional Liquidity Claim	0.00%
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | TruPs Collateralized Debt Obligation [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	21.00%	[2]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Probability of Paying a Conditional Liquidity Claim	45.00%
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | TruPs Collateralized Debt Obligation [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Principal Recovery Percent	50.00%
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Principal Recovery Rate Using Distressed Pricing Scenario	45.00%
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | NIMS derivative assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Derivative Assets	1,700,000	[1]
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | NIMS derivative assets | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	11.00%	[2]
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | NIMS derivative assets | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	21.00%	[2]
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | NIMS derivative assets | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, NIMS Spread	43.00%
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | NIMS VIEs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
VIE debt	8,600,000	[1]
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | NIMS VIEs [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	11.00%	[2]
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | NIMS VIEs [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	21.00%	[2]
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | NIMS VIEs [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	43.00%
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | CDO Of ABS Transaction [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
VIE debt	145,600,000	[1]
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | CDO Of ABS Transaction [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	11.00%	[2]
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | CDO Of ABS Transaction [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	21.00%	[2]
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | CDO Of ABS Transaction [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Principal Recovery Percent	16.30%
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | State and municipal obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Total Investments at Fair Value	58,100,000	[1]
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | State and municipal obligations | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Discount Rate	8.60%
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Expected Loss Rate	0.00%
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | State and municipal obligations | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Discount Rate	10.80%
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Expected Loss Rate	19.00%
Fair Value, Inputs, Level 3 | Discounted Cash Flow Valuation Technique [Member] | State and municipal obligations | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Discount Rate	10.10%
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Expected Loss Rate	6.30%
Fair Value, Inputs, Level 3 | Base Correlation Model Valuation Technique [Member] | Corporate collateralized debt obligations (CDO's)[Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Derivative Assets	11,200,000	[1]
Derivative liabilities	9,300,000	[1]
Fair Value, Inputs, Level 3 | Base Correlation Model Valuation Technique [Member] | Corporate collateralized debt obligations (CDO's)[Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Average Credit Spread	0.30%
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	11.00%	[2]
Fair Value, Inputs, Level 3 | Base Correlation Model Valuation Technique [Member] | Corporate collateralized debt obligations (CDO's)[Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Average Credit Spread	1.90%
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	21.00%	[2]
Fair Value, Inputs, Level 3 | Base Correlation Model Valuation Technique [Member] | Corporate collateralized debt obligations (CDO's)[Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, Correlation Factor	85.00%
Fair Value, Inputs, Level 3 | Risk-Based Model Valuation Technique [Member] | Non Corporate CDOS and other derivative transactions[Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Derivative liabilities	$ 58,900,000	[1]
Fair Value, Inputs, Level 3 | Risk-Based Model Valuation Technique [Member] | Non Corporate CDOS and other derivative transactions[Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	11.00%	[2]
Derivative, Expected Remaining Life	1 year
Fair Value, Inputs, Level 3 | Risk-Based Model Valuation Technique [Member] | Non Corporate CDOS and other derivative transactions[Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs, Additional Disclosure, CDS Spread Percent	21.00%	[2]
Derivative, Expected Remaining Life	20 years

[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.