Note 4 - Derivative Instruments Fair Values Derivatives, Balance Sheet Location by Derivative Contract Type (Details) (USD $) In Thousands, unless otherwise specified				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Financial Guaranty Credit Derivatives [Member]	Dec. 31, 2011 Financial Guaranty Credit Derivatives [Member]	Dec. 31, 2012 Financial Guaranty VIE Derivative Liabilities [Member]		Dec. 31, 2011 Financial Guaranty VIE Derivative Liabilities [Member]	Dec. 31, 2012 NIMS [Member]		Dec. 31, 2011 NIMS [Member]	Dec. 31, 2012 Radian Group Consolidated [Member]	Dec. 31, 2011 Radian Group Consolidated [Member]
Derivatives, Fair Value [Line Items]
Derivative, Remaining Maturity				5 years
Derivative Assets	$ 13,609	$ 17,212		$ 12,024	$ 15,432				$ 1,585		$ 1,780	$ 13,609	$ 17,212
Derivative liabilities	266,873	126,006	723,579	196,406	106,505	70,467	[1]	19,501				266,873	126,006
Derivative liabilities, net						$ (70,467)	[2]		$ 1,585	[3]		$ (253,264)	$ (108,794)

[1] As a result of the CDO Commutation Transactions described in Note 1, we established a VIE. See Note 6 for further details.

[2] Represents the fair value of a CDS included in a VIE, which we consolidate, relating to the Terminated TruPs CDOs. The assets in the VIE represent the only funds available to pay the CDS Counterparty for amounts due under the contract; therefore, the notional exposure presented for the CDS is limited to the current trust assets. See Notes 1 and 6 for information on the underlying reference securities and on our maximum exposure to loss from this consolidated financial guaranty transaction.

[3] Represents NIMS derivative assets related to consolidated NIMS VIEs. Also includes common stock warrants. Because none of these investments represent financial guaranty contracts that we issued, they cannot become liabilities, and therefore, do not represent additional par exposure.