Note 13 - Statutory Information Statutory Information (Details) (USD $)	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Statutory Accounting Practices [Line Items]
Restricted Net Assets Held by Consolidated Subsidiaries	$ 3,000,000,000
Radian Guaranty [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Net Income Amount	110,800,000	273,700,000
Statutory capital	1,349,400,000	1,325,200,000
Statutory contingency reserve	$ 487,600,000	$ 389,400,000

Funds separated from retained earnings and held to cover any unforeseen future business losses.

No definition available.

Name:	rdn_ContingencyReserve
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Period Type:	instant

- Definition

The amount of the entity's restricted net assets which are held by consolidated subsidiaries (entity's investment in subsidiaries).

+ References

No definition available.

+ Details

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- Details

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Period Type:	duration

- Definition

The amount of statutory capital and surplus (stockholders' equity) as of the balance sheet date using prescribed or permitted statutory accounting practices (rather than GAAP, if different) of the state or country.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.23(c))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 505

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6486098&loc=d3e24708-158529

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 24

-Subparagraph c

-Article 7

+ Details

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- Definition

Amount of net income for the period determined using accounting principles prescribed or permitted by insurance regulators.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Details

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