Note 14 - Statutory Information Other Capital and Liquidity (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Terminated TruPs Bonds Subject To An Event Of Default Occurring And Continuing After 2016 or 2017 [Member] | Radian Asset Assurance [Member]
Capital and Liquidity Line Items
Number Of Trups CDOs Terminated	4
Terminated TruPs Bonds [Member] | Radian Asset Assurance [Member]
Capital and Liquidity Line Items
Statutory Salvage Recovery	$ 75.9
Maximum [Member] | Radian Guaranty [Member] | Scenario, Forecast [Member] | Second Quota Share Reinsurance Transaction [Member]
Capital and Liquidity Line Items
First Lien Primary Mortgage Insurance Risk In Force Ceded	2,000
Maximum [Member] | Initial Quota Share Reinsurance Transaction [Member] | Radian Guaranty [Member] | Scenario, Forecast [Member]
Capital and Liquidity Line Items
Impact To Statutory Capital And Surplus	62.5
First Lien Primary Mortgage Insurance Risk In Force Ceded	1,600
Minimum [Member] | Radian Guaranty [Member] | Scenario, Forecast [Member] | Second Quota Share Reinsurance Transaction [Member]
Capital and Liquidity Line Items
First Lien Primary Mortgage Insurance Risk In Force Ceded	$ 750