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

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

- 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 SEC

-Name Regulation S-X (SX)

-Number 210

-Section 17

-Article 12

Reference 2: 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

Reference 3: 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 4: 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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 1

-Article 7

Reference 6: 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

+ 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

+ 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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 13

-Article 9

+ Details

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

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 7 - Reinsurance Reinsurance Transactions (Details) (Radian Guaranty [Member], USD $)	1 Months Ended	3 Months Ended		12 Months Ended
	Jan. 31, 2015	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2012 transaction
Reinsurance Transaction Details [Line Items]
Number of Quota Share Reinsurance Agreements					2
Initial Quota Share Reinsurance Transaction [Member]
Reinsurance Transaction Details [Line Items]
First Lien Primary Mortgage Insurance Risk In Force Ceded		$ 1,100,000,000
Ceded Premiums Written		4,067,000	5,304,000
Ceded Premiums Earned		6,018,000	6,807,000
Fees and Commissions		880,000	1,326,000
Ceded Insurance Commission Percentage		20.00%		25.00%
Percentage of Ceded Insurance Subjected to Change in Commission Percentage	66.67%
Second Quota Share Reinsurance Transaction [Member]
Reinsurance Transaction Details [Line Items]
First Lien Primary Mortgage Insurance Risk In Force Ceded		1,500,000,000
Ceded Premiums Written		6,529,000	7,293,000
Ceded Premiums Earned		8,768,000	6,585,000
Fees and Commissions		2,285,000	2,553,000
Maximum [Member] \| Initial Quota Share Reinsurance Transaction [Member]
Reinsurance Transaction Details [Line Items]
First Lien Primary Mortgage Insurance Risk In Force Ceded		1,600,000,000
Maximum [Member] \| Second Quota Share Reinsurance Transaction [Member]
Reinsurance Transaction Details [Line Items]
First Lien Primary Mortgage Insurance Risk In Force Ceded		$ 1,600,000,000