Name:	rdn_DecreaseToOurLossReservesDueToEstimatedRescissionsAndDenials
Namespace Prefix:	rdn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

This concept represents the rate at which defaulted loans that have reached the stage where the foreclosure sale has been scheduled or held are expected to result in a claim.

No definition available.

Name:	rdn_DefaultToClaimEstimateGrossForForeclosureStageDefaults
Namespace Prefix:	rdn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

This concept represents the rate at which newly reported defaulted loans are expected to result in a claim.

No definition available.

Name:	rdn_DefaultToClaimRateEstimateGrossForNewDefaults
Namespace Prefix:	rdn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

This concept represents the rate at which defaulted loans that have not yet reached the foreclosure stage are expected to result in a claim.

No definition available.

Name:	rdn_DefaultToClaimRateEstimateGrossForPreForeclosureStageDefaults
Namespace Prefix:	rdn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The concept represents the rate at which defaulted loans are expected to result in claim net of denials, rescissions and reinstatements.

No definition available.

Name:	rdn_WeightedAverageDefaultToClaimRateAssumptionNetOfDenialsRescissionsAndReinstatements
Namespace Prefix:	rdn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Estimated costs as of the balance sheet date of settling insured claims and costs incurred in the claims settlement process for claims that have not yet been submitted to the insurance company for reimbursement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 5.W)
-URI http://asc.fasb.org/extlink&oid=27015833&loc=d3e570705-122907