Name:	rdn_ChangeInPresentValueofEstimatedCreditLossPayments
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The increase (decrease) during the reporting period in goodwill and intangible assets which includes amortization, impairment, etc.

No definition available.

Name:	rdn_IncreaseDecreaseinGoodwillandIntangibleAssets
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Period Type:	duration

This concept represents the total of net gains/losses on investments, net gains/losses on other financial instruments, and any other gains on financial instruments for the purposes of reconciling net income (loss) from segments to consolidated results.

No definition available.

Name:	rdn_NetGainsLossesonAllFinancialInstruments
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This concept represents the adjusted pre-tax operating income (loss) for segment reporting (non GAAP) and only includes the revenue and expense items that management considers in assessing the performance of the segment businesses.

No definition available.

Name:	rdn_OperatingIncomeLossPreTaxNonGAAP
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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 25

-Paragraph 23

-URI http://asc.fasb.org/extlink&oid=34752592&loc=d3e1043-128460

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Costs of sales and operating expenses for the period incurred from transactions with related parties.

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The net result for the period of deducting operating expenses from operating revenues.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(e))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Related Parties

-URI http://asc.fasb.org/extlink&oid=16382449

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.6-07.1(c))

-URI http://asc.fasb.org/extlink&oid=6488393&loc=d3e606610-122999

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 07

-Paragraph b

-Subparagraph 1

-Article 6

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Name:	us-gaap_StatementBusinessSegmentsAxis=rdn_MortgageInsuranceandMortgageandRealEstateServicesSegmentsMember
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