Note 15 - Statutory Information Statutory Information (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Jun. 30, 2011
Statutory Accounting Practices [Line Items]
States Which Have A Risk To Capital Ratio Limit of 25 To 1	11
Additional Risk And Capital Information
Policyholder Dividends, Rate on Policy Earnings		10.00%
STAT Accounting Information [Abstract]
Mortgage Guaranty Insurance Companies Are Required Each Year To Establish A Contingency Reserve Equal To This Percentage Of Premiums Earned In Such Year	50.00%
Number Of Years A Fifty Percent Contingency Reserve Is Required To Be Maintained	10
Mortgage Guaranty Insurance Companies Contingency Reserve May Be Reduced With Regulatory Approval To The Extent That Losses In Any Calendar Year Exceed This Percentage Of Earned Premiums For Such Year	35.00%
For Financial Guaranty Policies, Each Insurer Must Establish A Contingency Reserve Equal To The Greater Of This Percentage Of Premiums Written Or A Stated Percentage Of The Principal Guaranteed	50.00%
Range Of Years The Contingency Reserve Must Be Maintained, Low End	15
Range Of Years The Contingency Reserve Must Be Maintained, High End	20
Radian Guaranty [Member]
Statutory Accounting Practices [Line Items]
Statutory Unassigned Negative Surplus	$ 767,700,000	$ 168,600,000
Statutory net (loss) income	(545,100,000)	(535,200,000)	(211,800,000)
Statutory policyholers' surplus	843,200,000	1,295,700,000	741,300,000
Statutory contingency reserve	0	19,600,000	770,500,000
Additional Risk And Capital Information
Insurance Risk Ceded To Affiliates	2,500,000,000			2,000,000,000
Capital Contributions	30,000,000	322,000,000
Capital Contribution Receivable	100,000,000
Consolidation, Wholly Owned Subsidiary, Parent Ownershi Interest Changes, Transfer of Interest by Parent	17,000,000
Payments for (Proceeds from) Businesses and Interest in Affiliates	6,000,000
Radian Insurance [Member]
Statutory Accounting Practices [Line Items]
Statutory Unassigned Negative Surplus	379,100,000	384,100,000
Statutory net (loss) income	4,300,000	43,900,000	19,900,000
Statutory policyholers' surplus	156,800,000	151,700,000	108,900,000
Statutory contingency reserve	0	1,500,000	0
Additional Risk And Capital Information
Required statutory surplus	20,000,000
Radian Mortgage Assurance [Member]
Statutory Accounting Practices [Line Items]
Statutory Unassigned Negative Surplus	162,500,000	161,900,000
Statutory net (loss) income	(600,000)	7,400,000	(17,900,000)
Statutory policyholers' surplus	16,500,000	17,100,000	9,600,000
Additional Risk And Capital Information
Required statutory surplus	1,125,000
MInimum Statutory Surplus Committted To Be Maintained Each Quarter	5,000,000
CMAC Of Texas [Member]
Statutory Accounting Practices [Line Items]
Statutory net (loss) income	(46,600,000)	(194,700,000)	(67,000,000)
Statutory policyholers' surplus	26,200,000	40,800,000	122,500,000
Additional Risk And Capital Information
Capital Contributions	23,000,000
Required statutory surplus	20,000,000
Radian Mortgage Insurance [Member]
Statutory Accounting Practices [Line Items]
Statutory net (loss) income	(11,100,000)	(60,600,000)	(34,200,000)
Statutory policyholers' surplus	20,000,000	10,100,000	300,000
Additional Risk And Capital Information
Capital Contributions	10,500,000
Minimum Policyholder Position	5,400,000
Radian Asset Assurance
Statutory Accounting Practices [Line Items]
Statutory net (loss) income	69,100,000	58,000,000	42,800,000
Statutory policyholers' surplus	973,900,000	1,048,600,000	1,059,100,000
Statutory contingency reserve	421,400,000	392,600,000	366,100,000
Additional Risk And Capital Information
Claims Paying Resources	2,200,000,000
Required statutory surplus	66,400,000
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	53,400,000	69,200,000	99,700,000
Statutory Minimum Policyholders' Surplus Required For Financial Guaranty Insurers In The State Of New York	65,000,000
Statutory Minimum Policyholders' Surplus Required For Other Lines Of Insurance By The State Of New York	$ 1,400,000
NEW YORK
Additional Risk And Capital Information
The Insured Average Annual Debt Service For A Single Risk, Net Of Reinsurance And Collateral, May Not Exceed This Percentage Of The Sum Of The Insurer's Policyholders' Surplus And Contingency Reserves	10.00%
Insured Principal Of Municipal Bonds Attributable To Any Single Risk, Net Of Reinsurance And Collateral, Is Limited To This Percentage Of The Insurer's Policyholders' Surplus And Contingency Reserves	75.00%