Percentage of commissions due to ceded insurance.

No definition available.

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

- Definition

First Lien Primary Mortgage Insurance Risk In Force Ceded

+ References

No definition available.

+ Details

Name:	rdn_FirstLienPrimaryMortgageInsuranceRiskInForceCeded
Namespace Prefix:	rdn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This concept represents the number of quota share reinsurance agreements the company has entered into with third party reinsurance providers.

+ References

No definition available.

+ Details

Name:	rdn_NumberofQuotaShareReinsuranceAgreements
Namespace Prefix:	rdn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of reinsurance able to be recaptured, as per the quota share reinsurance agreement.

+ References

No definition available.

+ Details

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

- Definition

The percentage of the entity's ceded risk related to a quota share arrangement which was subjected to a change in ceding commission percentage.

+ References

No definition available.

+ Details

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

- Definition

[Line Items] for Tabular disclosure of amounts related to premiums written, earned as well as commissions on ceded business that was part of Quota Share Reinsurance transactions.

+ References

No definition available.

+ Details

Name:	rdn_ReinsuranceTransactionDetailsLineItems
Namespace Prefix:	rdn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of earned premiums ceded to other entities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.1)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 605

-Section 50

-Paragraph 1

-Subparagraph (b),(c)(2)

-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 605

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6486662&loc=d3e27175-158546

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 235

-Section S99

-Paragraph 2

-Subparagraph (SX 210.12-17)

-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915

+ Details

Name:	us-gaap_CededPremiumsEarned
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of written premiums ceded to other entities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 605

-Section 50

-Paragraph 1

-Subparagraph (b),(c)(2)

-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 17

-Article 12

+ Details

Name:	us-gaap_CededPremiumsWritten
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of fees and commissions from financial services and banking activities and correspondent clearing. Includes fees from depositor accounts, credit cards, merchant discounts, and fiduciary and trust activities, guarantee fees, investment advisory, management, and administrative fees, transfer agent fees, and insurance commissions.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.13)

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

Name:	us-gaap_FeesAndCommissions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Income from agency and brokerage operations (includes sales of annuities and supplemental contracts); service charges, commissions, and fees from the sale of insurance and related services; and management fees from separate accounts, deferred annuities, and universal life products.

+ References

+ Details

Name:	us-gaap_InsuranceCommissionsAndFees
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=rdn_RadianGuarantyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rdn_CapitalAndLiquidityAxis=rdn_InitialQuotaShareReinsuranceTransactionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	rdn_CapitalAndLiquidityAxis=rdn_SecondQuotaShareReinsuranceTransactionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
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Period Type:

Note 7 - Reinsurance Reinsurance Transactions (Details) - Radian Guaranty [Member] $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2014	Dec. 31, 2012 transaction
Reinsurance Transaction Details [Line Items]
Number of Quota Share Reinsurance Agreements \| transaction						2
Initial Quota Share Reinsurance Transaction [Member]
Reinsurance Transaction Details [Line Items]
Ceded Premiums Written	$ 3,822	$ 5,046	$ 7,889	$ 10,350
Ceded Premiums Earned	6,424	6,803	12,442	13,610
Fees and Commissions	828	1,262	$ 1,708	2,588
Ceded Insurance Commission Percentage			20.00%		25.00%
First Lien Primary Mortgage Insurance Risk In Force Ceded	1,000,000		$ 1,000,000
Percentage of Ceded Insurance Subjected to Change in Commission Percentage			66.70%
Second Quota Share Reinsurance Transaction [Member]
Reinsurance Transaction Details [Line Items]
Ceded Premiums Written	395	8,072	$ 6,924	15,365
Ceded Premiums Earned	3,039	7,197	11,807	13,782
Fees and Commissions	$ 2,154	$ 2,825	$ 4,439	$ 5,378
Percentage of Ceded Insurance Subjected to Change in Commission Percentage	50.00%		50.00%
Insurance Commissions and Fees	$ 5,800		$ 5,800
First Lien Primary Mortgage Insurance Risk In Force Ceded	1,400,000		1,400,000
Maximum [Member] \| Initial Quota Share Reinsurance Transaction [Member]
Reinsurance Transaction Details [Line Items]
First Lien Primary Mortgage Insurance Risk In Force Ceded	1,600,000		1,600,000
Maximum [Member] \| Second Quota Share Reinsurance Transaction [Member]
Reinsurance Transaction Details [Line Items]
First Lien Primary Mortgage Insurance Risk In Force Ceded	$ 0		$ 0