Note 4 - Fair Value of Financial Instruments Fair Value Assets Liabilities by Hierarchy Level (Details) (USD $)	Jun. 30, 2012		Dec. 31, 2011
Fair Value by Hierarchy Level Assets and Liabilities
Derivative Assets	$ 14,229,000		$ 17,212,000
Derivative liabilities	219,960,000		126,006,000
VIE debt	107,833,000		228,240,000
Fixed-maturities held to maturity	2,524,000		2,748,000
Consolidated Financial Guaranty Insurance Contracts [Member]
Fair Value by Hierarchy Level Assets and Liabilities
Derivative Assets	0		0
Derivative liabilities	75,400,000		19,500,000
VIE debt	100,300,000		218,800,000
Number Of Consolidated Other Financial Guaranty Transactions	2
Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	5,193,600,000	[1]	5,719,900,000	[2]
Derivative Assets	14,200,000		17,200,000
Other Assets	100,700,000	[3]	104,000,000	[4]
Total Assets at Fair Value	5,308,500,000		5,841,100,000
Derivative liabilities	220,000,000		126,000,000
VIE debt	107,800,000	[5]	228,200,000	[6]
Total Liabilities at Fair Value	327,800,000		354,200,000
Fair Value, Measurements, Recurring | Consolidated Financial Guaranty Insurance Contracts [Member]
Fair Value by Hierarchy Level Assets and Liabilities
Number Of Consolidated Other Financial Guaranty Transactions	2		2
US government and agency securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	952,700,000		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	854,000,000		1,047,500,000
Money market instruments | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	468,900,000		723,200,000
Corporate bonds and notes | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	836,000,000		700,500,000
RMBS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	968,700,000		930,200,000
CMBS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	185,200,000		225,800,000
CDO | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	0		5,500,000
Other ABS | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	133,700,000		99,900,000
Foreign government securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	109,100,000		102,900,000
Hybrid securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	353,900,000		346,300,000
Equity securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	252,500,000	[7]	269,200,000	[7]
Other investments | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	78,900,000	[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	798,600,000	[1]	1,226,100,000	[2]
Derivative Assets	0		0
Other Assets	0	[3]	0	[4]
Total Assets at Fair Value	798,600,000		1,226,100,000
Derivative liabilities	0		0
VIE debt	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	235,200,000		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	468,900,000		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		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	94,500,000	[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	4,292,100,000	[1]	4,329,600,000	[2]
Derivative Assets	0		200,000
Other Assets	0	[3]	0	[4]
Total Assets at Fair Value	4,292,100,000		4,329,800,000
Derivative liabilities	0		0
VIE debt	0	[5]	0	[6]
Total Liabilities at Fair Value	0		0
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value by Hierarchy Level Assets and Liabilities
Fixed-maturities held to maturity	2,500,000	[10]	2,600,000	[10]
Other invested assets fair value disclosure	59,100,000	[10]	61,000,000	[10]
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	717,500,000		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	834,400,000		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	836,000,000		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	968,700,000		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	185,200,000		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		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	128,900,000		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	109,100,000		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	353,900,000		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	156,000,000	[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	2,400,000	[8]	151,600,000	[9]
Fair Value, Inputs, Level 2 | Commercial Paper [Member] | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	700,000
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	1,700,000		1,600,000
Fair Value, Inputs, Level 3
Fair Value by Hierarchy Level Assets and Liabilities
Total Level III Assets	4.10%
Total Level III Liabilities	100.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	102,900,000	[1]	164,200,000	[2]
Derivative Assets	14,200,000		17,000,000
Other Assets	100,700,000	[3]	104,000,000	[4]
Total Assets at Fair Value	217,800,000		285,200,000
Derivative liabilities	220,000,000		126,000,000
VIE debt	107,800,000		228,200,000
Total Liabilities at Fair Value	327,800,000		354,200,000
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | NIMS [Member]
Fair Value by Hierarchy Level Assets and Liabilities
VIE debt	7,500,000		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	100,300,000		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	19,600,000		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	0		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	4,800,000		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	2,000,000	[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	76,500,000	[8]	6,800,000	[9]
Fair Value, Inputs, Level 3 | Lottery Annuities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	1,100,000		1,600,000
Fair Value, Inputs, Level 3 | Consolidated Committed Preferred Custodial Trust Securities | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value			5,200,000
Fair Value, Inputs, Level 3 | Investment Contracts [Member] | Fair Value, Measurements, Recurring
Fair Value by Hierarchy Level Assets and Liabilities
Total Investments at Fair Value	$ 75,400,000

[1] Does not include fixed-maturities held to maturity ($2.5 million) and certain other invested assets ($59.1 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 ($7.5 million) and amounts related to financial guaranty VIEs ($100.3 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 ($0.7 million) and short-term CDs ($1.7 million) included within Level II, and lottery annuities ($1.1 million) and a guaranteed investment contract held by a consolidated VIE ($75.4 million) within Level III.

[9] Comprising short-term commercial paper within Committed Preferred Custodial Trust Securities (“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.

[10] These estimated fair values would be classified in Level II of the fair value hierarchy.