Note 3 - Derivative Instruments Fair Values Derivatives, Balance Sheet Location by Derivative Contract Type (Details) (USD $) In Thousands, unless otherwise specified													3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Financial Guaranty Credit Derivatives [Member]	Dec. 31, 2012 Financial Guaranty Credit Derivatives [Member]	Mar. 31, 2013 Net Interest Margin Securities Related And Other [Member]		Dec. 31, 2012 Net Interest Margin Securities Related And Other [Member]	Mar. 31, 2013 Financial Guaranty VIE Derivative Liabilities [Member]		Dec. 31, 2012 Financial Guaranty VIE Derivative Liabilities [Member]	Mar. 31, 2013 Radian Group Consolidated [Member]	Dec. 31, 2012 Radian Group Consolidated [Member]	Mar. 31, 2013 Majority [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	$ 6,429	$ 13,609	$ 4,851	$ 12,024	$ 1,578		$ 1,585				$ 6,429	$ 13,609
Derivative liabilities	430,898	266,873	364,146	196,406				66,752		70,467	430,898	266,873
Derivative liabilities, net					$ 1,578	[1]		$ (66,752)	[2]		$ (424,469)	$ (253,264)
Derivative, Remaining Maturity													5 years

[1] Represents NIMS derivative assets related to consolidated NIMS VIEs. Because these investments represent financial guaranty contracts that we issued, they cannot become liabilities, and therefore, do not represent additional par exposure.

[2] Represents the fair value of a CDS included in a VIE that we have consolidated. See Note 5 for more information on this transaction, the underlying reference securities and our maximum exposure to loss from this consolidated financial guaranty transaction. 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.