Name:	rdn_AllocatedNonShareBasedCompensationExpense
Namespace Prefix:	rdn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Share-based Compensation Arrangement by Share-based Payment Award, Performance Period

No definition available.

Name:	rdn_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod
Namespace Prefix:	rdn_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

Share-based Compensation, Cash Payout Amount as Percentage of Target Award

No definition available.

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

Share-based Compensation, Performance Target Weight as Percentage of Total Performance Target

No definition available.

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

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(2)(c)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.