Note 5 - Fair Value of Financial Instruments Fair Value Assets Liabilities by Hierarchy Level (Details) (USD $)	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Fair Value by Hierarchy Level Assets and Liabilities
Derivative Assets	$ 13,609,000		$ 17,212,000
Derivative liabilities	266,873,000		126,006,000		723,579,000
VIE debt - at fair value	108,858,000		228,240,000		520,114,000
Fixed-maturities held to maturity	676,000		2,748,000
NIMS VIEs [Member]
Fair Value by Hierarchy Level Assets and Liabilities
Derivative Assets	1,585,000		1,602,000
VIE debt - at fair value	9,875,000		9,450,000
Consolidated Financial Guaranty Insurance Contracts [Member]
Fair Value by Hierarchy Level Assets and Liabilities
Derivative Assets	0		0
Derivative liabilities	70,467,000		19,501,000
VIE debt - at fair value	98,983,000		218,790,000
Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	5,103,000,000	[1]	5,719,900,000	[2]
Derivative Assets	13,600,000		17,200,000
Other Assets	99,200,000	[3]	104,000,000	[4]
Total Assets at Fair Value	5,215,800,000		5,841,100,000
Derivative liabilities	266,900,000		126,000,000
VIE debt - at fair value	108,900,000	[5]	228,200,000	[6]
Total Liabilities at Fair Value	375,800,000		354,200,000
Fair Value, Measurements, Recurring | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value by Hierarchy Level Assets and Liabilities
Fixed-maturities held to maturity	700,000		2,600,000
Other invested assets fair value disclosure	48,700,000		61,000,000
US government and agency securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	571,600,000		1,110,500,000
State and municipal obligations | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	688,000,000		1,047,500,000
Money market instruments | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	638,000,000		723,200,000
Corporate bonds and notes | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	1,373,600,000		700,500,000
RMBS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	663,400,000		930,200,000
CMBS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	237,300,000		225,800,000
CDO | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value			5,500,000
Other ABS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	254,100,000		99,900,000
Foreign government securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	117,700,000		102,900,000
Hybrid securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	211,900,000		346,300,000
Equity securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	265,900,000	[7]	269,200,000	[7]
Other investments | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	81,500,000	[8]	158,400,000	[9]
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	874,700,000	[1]	1,226,100,000	[2]
Derivative Assets	0		0
Other Assets	0	[3]	0	[4]
Total Assets at Fair Value	874,700,000		1,226,100,000
Derivative liabilities	0		0
VIE debt - at fair value	0	[5]	0	[6]
Total Liabilities at Fair Value	0		0
Fair Value, Inputs, Level 1 | US government and agency securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	137,800,000		386,900,000
Fair Value, Inputs, Level 1 | State and municipal obligations | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		0
Fair Value, Inputs, Level 1 | Money market instruments | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	638,000,000		723,200,000
Fair Value, Inputs, Level 1 | Corporate bonds and notes | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		0
Fair Value, Inputs, Level 1 | RMBS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		0
Fair Value, Inputs, Level 1 | CMBS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		0
Fair Value, Inputs, Level 1 | CDO | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value			0
Fair Value, Inputs, Level 1 | Other ABS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		0
Fair Value, Inputs, Level 1 | Foreign government securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		0
Fair Value, Inputs, Level 1 | Hybrid securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		0
Fair Value, Inputs, Level 1 | Equity securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	98,900,000	[7]	116,000,000	[7]
Fair Value, Inputs, Level 1 | Other investments | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0	[8]	0	[9]
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	4,127,600,000	[1]	4,329,600,000	[2]
Derivative Assets	0		200,000
Other Assets	0	[3]	0	[4]
Total Assets at Fair Value	4,127,600,000		4,329,800,000
Derivative liabilities	0		0
VIE debt - at fair value	0	[5]	0	[6]
Total Liabilities at Fair Value	0		0
Fair Value, Inputs, Level 2 | Trust Preferred Securities [Member] | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	900,000
Fair Value, Inputs, Level 2 | US government and agency securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	433,800,000		723,600,000
Fair Value, Inputs, Level 2 | State and municipal obligations | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	669,000,000		985,000,000
Fair Value, Inputs, Level 2 | Money market instruments | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		0
Fair Value, Inputs, Level 2 | Corporate bonds and notes | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	1,373,600,000		700,500,000
Fair Value, Inputs, Level 2 | RMBS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	663,400,000		884,700,000
Fair Value, Inputs, Level 2 | CMBS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	237,300,000		190,400,000
Fair Value, Inputs, Level 2 | CDO | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value			0
Fair Value, Inputs, Level 2 | Other ABS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	252,400,000		97,000,000
Fair Value, Inputs, Level 2 | Foreign government securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	117,700,000		102,900,000
Fair Value, Inputs, Level 2 | Hybrid securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	211,900,000		341,500,000
Fair Value, Inputs, Level 2 | Equity securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	166,000,000	[7]	152,400,000	[7]
Fair Value, Inputs, Level 2 | Other investments | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	2,500,000	[8]	151,600,000	[9]
Fair Value, Inputs, Level 2 | Committed Preferred Securities CPS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value			150,000,000
Fair Value, Inputs, Level 2 | Short Term CDs | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	1,600,000		1,600,000
Fair Value, Inputs, Level 3
Fair Value by Hierarchy Level Assets and Liabilities
Number Of Consolidated Other Financial Guaranty Transactions	2		2
Fair Value, Inputs, Level 3 | Consolidated Financial Guaranty Insurance Contracts [Member]
Fair Value by Hierarchy Level Assets and Liabilities
VIE debt - at fair value	99,000,000
Number Of Consolidated Other Financial Guaranty Transactions	2
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	100,700,000	[1]	164,200,000	[2]
Derivative Assets	13,600,000		17,000,000
Other Assets	99,200,000	[3]	104,000,000	[4]
Total Assets at Fair Value	213,500,000		285,200,000
Derivative liabilities	266,900,000		126,000,000
VIE debt - at fair value	108,900,000	[5]	228,200,000	[6]
Total Liabilities at Fair Value	375,800,000		354,200,000
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | NIMS VIEs [Member]
Fair Value by Hierarchy Level Assets and Liabilities
VIE debt - at fair value	9,900,000		9,400,000
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Consolidated Financial Guaranty Insurance Contracts [Member]
Fair Value by Hierarchy Level Assets and Liabilities
VIE debt - at fair value	99,000,000		218,800,000
Fair Value, Inputs, Level 3 | US government and agency securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		0
Fair Value, Inputs, Level 3 | State and municipal obligations | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	19,000,000		62,500,000
Fair Value, Inputs, Level 3 | Money market instruments | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		0
Fair Value, Inputs, Level 3 | Corporate bonds and notes | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		0
Fair Value, Inputs, Level 3 | RMBS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		45,500,000
Fair Value, Inputs, Level 3 | CMBS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		35,400,000
Fair Value, Inputs, Level 3 | CDO | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value			5,500,000
Fair Value, Inputs, Level 3 | Other ABS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	1,700,000		2,900,000
Fair Value, Inputs, Level 3 | Foreign government securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		0
Fair Value, Inputs, Level 3 | Hybrid securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		4,800,000
Fair Value, Inputs, Level 3 | Equity securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	1,000,000	[7]	800,000	[7]
Fair Value, Inputs, Level 3 | Other investments | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	79,000,000	[8]	6,800,000	[9]
Fair Value, Inputs, Level 3 | Lottery Annuities
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value			1,600,000
Fair Value, Inputs, Level 3 | Lottery Annuities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	1,000,000
Fair Value, Inputs, Level 3 | Guaranteed Investment Contract Held by a Consolidated VIE [Member] | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	78,000,000
Fair Value, Inputs, Level 3 | Trust Preferred Securities Held by Consolidated VIE [Member] | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value			$ 5,200,000

[1] Does not include fixed-maturities held to maturity ($0.7 million) and certain other invested assets ($48.7 million), primarily invested in limited partnerships, accounted for as cost-method investments and not measured at fair value.

[2] Does not include fixed-maturities held to maturity ($2.6 million) and other invested assets ($61.0 million), primarily invested in limited partnerships, accounted for as cost-method investments and not measured at fair value.

[3] Primarily comprising manufactured housing loan collateral related to two consolidated financial guaranty VIEs.

[4] Comprising manufactured housing loan collateral related to two consolidated financial guaranty VIEs.

[5] Comprising consolidated debt related to NIMS VIEs ($9.9 million) and amounts related to financial guaranty VIEs ($99.0 million).

[6] Comprising consolidated debt related to NIMS VIEs ($9.4 million) and amounts related to financial guaranty VIEs ($218.8 million).

[7] Comprising broadly diversified domestic equity mutual funds included within Level I and various preferred and common stocks invested across numerous companies and industries included within Levels II and III.

[8] Comprising TruPs ($0.9 million) and short-term CDs ($1.6 million) included within Level II and lottery annuities ($1.0 million) and a guaranteed investment contract held by a consolidated VIE ($78.0 million) within Level III.

[9] Comprising short-term commercial paper within CPS trusts ($150.0 million) and short-term CDs ($1.6 million ) included within Level II and lottery annuities ($1.6 million) and TruPs held by consolidated VIEs ($5.2 million) included within Level III.