Note 4 - Fair Value of Financial Instruments Fair Value Assets Liabilities by Hierarchy Level (Details) (USD $)	Jun. 30, 2011		Dec. 31, 2010
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	$ 27,266,000		$ 26,212,000
Variable interest entity debt	393,740,000		520,114,000
Derivative liabilities	313,708,000		723,579,000
Held-to-maturity Securities, Fair Value Disclosure	8,282,000		11,416,000
US government and agency securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	618,200,000		1,075,000,000
US government and agency securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	672,600,000		731,400,000
US government and agency securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
US government and agency securities [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	1,290,800,000		1,806,400,000
State and municipal obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
State and municipal obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	1,015,100,000		1,159,700,000
State and municipal obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	23,600,000		23,200,000
State and municipal obligations [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	1,038,700,000		1,182,900,000
Money market instruments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	360,400,000		310,900,000
Money market instruments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
Money market instruments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
Money market instruments [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	360,400,000		310,900,000
Corporate bonds and notes [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
Corporate bonds and notes [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	865,200,000		1,060,400,000
Corporate bonds and notes [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
Corporate bonds and notes [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	865,200,000		1,060,400,000
RMBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
RMBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	954,600,000		913,500,000
RMBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	61,400,000		52,500,000
RMBS [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	1,016,000,000		966,000,000
CMBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
CMBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	190,400,000		173,600,000
CMBS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	29,400,000		23,000,000
CMBS [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	219,800,000		196,600,000
CDO [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
CDO [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
CDO [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	3,900,000		2,400,000
CDO [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	3,900,000		2,400,000
Other ABS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
Other ABS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	114,100,000		131,100,000
Other ABS [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	2,000,000		3,300,000
Other ABS [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	116,100,000		134,400,000
Foreign government securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
Foreign government securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	101,600,000		83,500,000
Foreign government securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
Foreign government securities [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	101,600,000		83,500,000
Hybrid securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
Hybrid securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	367,800,000		318,900,000
Hybrid securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0		0
Hybrid securities [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	367,800,000		318,900,000
Equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	176,900,000	[1]	168,400,000	[1]
Equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	198,500,000	[1]	168,600,000	[1]
Equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	5,600,000	[1]	2,900,000	[1]
Equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	381,000,000	[1]	339,900,000	[1]
Other investments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0	[2]	0	[3]
Other investments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	151,600,000	[2]	150,000,000	[3]
Other investments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	5,800,000	[2]	4,600,000	[3]
Other investments [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	157,400,000	[2]	154,600,000	[3]
Investments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	1,155,500,000	[4]	1,554,300,000	[5]
Investments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	4,631,500,000	[4]	4,890,700,000	[5]
Investments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	131,700,000	[4]	111,900,000	[5]
Investments [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	5,918,700,000	[4]	6,556,900,000	[5]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0		0
Other Assets	0	[6]	0	[6]
Assets, Fair Value Disclosure	1,155,500,000		1,554,300,000
Total Liabilities at Fair Value	0		0
Variable interest entity debt	0	[7]	0	[8]
Derivative liabilities	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	400,000		0
Other Assets	0	[6]	0	[6]
Assets, Fair Value Disclosure	4,631,900,000		4,890,700,000
Total Liabilities at Fair Value	0		0
Variable interest entity debt	0	[7]	0	[8]
Derivative liabilities	0		0
Committed Preferred Custodial Trust Securities	150,000,000
Financial Instruments, Owned, Short Term CD's, Fair Value Disclosure	1,600,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	26,900,000		26,200,000
Other Assets	113,700,000	[6]	109,700,000	[6]
Assets, Fair Value Disclosure	272,300,000		247,800,000
Total Liabilities at Fair Value	707,400,000		1,243,700,000
Variable interest entity debt	393,700,000	[7]	520,100,000	[8]
Derivative liabilities	313,700,000		723,600,000
Lottery Annuities, Other Investments, Fair Value	1,800,000
Financial Instruments, TruPs Held By Consolidated VIEs, at Fair Value	4,000,000
Variable Interest Entity Debt, NIMS, at Fair Value	56,200,000		141,000,000
Variable Interest Entity Debt, Financial Guaranty Contracts, at Fair Value	337,500,000		379,100,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	27,300,000		26,200,000
Other Assets	113,700,000	[6]	109,700,000	[6]
Assets, Fair Value Disclosure	6,059,700,000		6,692,800,000
Total Liabilities at Fair Value	707,400,000		1,243,700,000
Variable interest entity debt	393,700,000	[7]	520,100,000	[8]
Derivative liabilities	313,700,000		723,600,000
Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value Disclosure	7,781,000		10,773,000
Short Term Investments (Carried at Cost) Fair Value Disclosure	0		1,600,000
Other invested assets fair value disclosure	62,334,000		59,627,000
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Lottery Annuities, Other Investments, Fair Value			2,600,000
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Level III Assets	4.49362%
Total Level III Liabilities	100.00%
Financial Instruments, TruPs Held By Consolidated VIEs, at Fair Value			2,000,000
Number Of Consolidated Other Financial Guaranty Transactions	2
Unconsolidated Financial Guaranty Insurance Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	5,600,000		6,000,000
Variable interest entity debt	0		0
Derivative liabilities	258,500,000		585,900,000
Consolidated Financial Guaranty Insurance Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0		0
Variable interest entity debt	337,500,000		379,100,000
Derivative liabilities	$ 18,831,000	[9]	$ 19,226,000
Number Of Consolidated Other Financial Guaranty Transactions	2

[1] Comprised of 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.

[2] Comprised of short-term commercial paper within CPS trusts ($150.0 million) and short-term CDs ($1.6 million) included within Level II, and lottery annuities ($1.8 million) and TruPs held by consolidated VIEs ($4.0 million) included within Level III.

[3] Comprised of short-term commercial paper within CPS trusts included within Level II, and lottery annuities ($2.6 million) and TruPs held by consolidated VIEs ($2.0 million) included within Level III.

[4] Does not include fixed-maturities held to maturity ($7.8 million) and other invested assets ($62.3 million), primarily invested in limited partnerships, accounted for as cost-method investments and not measured at fair value.

[5] Does not include fixed-maturities held to maturity ($10.8 million), certain short-term investments ($1.6 million), primarily invested in CDs and time deposits, and other invested assets ($59.6 million), primarily invested in limited partnerships, accounted for as cost-method investments and not measured at fair value.

[6] Comprised of manufactured housing loan collateral related to two consolidated financial guaranty VIEs.

[7] Comprised of consolidated debt related to NIMS VIEs ($56.2 million) and amounts related to financial guaranty VIEs ($337.5 million).

[8] Comprised of consolidated debt related to NIMS VIEs ($141.0 million) and amounts related to financial guaranty VIEs ($379.1 million) that required consolidation as of January 1, 2010, under the accounting standard update regarding improvements to financial reporting by enterprises involving VIEs.

[9] Represents the fair value of an interest rate swap included in the consolidation of one of our financial guaranty transactions. The notional amount of the interest rate swap does not represent additional par exposure, and therefore, is excluded from this table. See Note 5 for information on our maximum exposure to loss from our consolidated financial guaranty transactions.