Note 14 - Statutory Information Risk to Capital (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	3 Months Ended
Mar. 31, 2012 Quota Share Reinsurance Agreement [Member] Radian Guaranty [Member] Scenario, Forecast [Member] Minimum [Member]	Mar. 31, 2012 Quota Share Reinsurance Agreement [Member] Radian Guaranty [Member] Scenario, Forecast [Member] Maximum [Member]	Jun. 30, 2012 Terminated TruPs Bonds [Member] Radian Asset Assurance [Member]
Capital and Liquidity Line Items
Impact To Statutory Capital And Surplus	$ 50.0	$ 62.5
Statutory Gain (Loss) on Contract Termination			7
Statutory Salvage Recovery			$ 75

Statutory gain (loss) related to the termination of a contract between the parties. The termination may be due to many causes including early termination of a lease by a lessee, a breach of contract by one party, or a failure to perform.

No definition available.

Name:	rdn_StatutoryGainLossOnContractTermination
Namespace Prefix:	rdn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration