Note 1 - Condensed Consolidated Financial Statements - Basis of Presentation and Business Overview Capital and Liquidity (Details) $ in Thousands			1 Months Ended	3 Months Ended			9 Months Ended
		Apr. 01, 2015	Jun. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) segment	Sep. 30, 2014 USD ($)	Jun. 18, 2015 USD ($)	Dec. 31, 2014 USD ($)
Basis of Presentation and Business Overview [Line Items]
Net cash provided by (used in) operating activities, continuing operations					$ 666		$ (5,993)	$ (192,271)
Cash Provided by (Used in) Operating Activities, Discontinued Operations					1,759		1,759	29,891
Cash Provided by (Used in) Investing Activities, Discontinued Operations					4,999		(4,999)	(161,070)
Cash and Cash Equivalents, Period Increase (Decrease) Including Discontinued Operations					29,979		38,144	8,050
Net Cash Provided by (Used in) Discontinued Operations					(3,240)		$ (421)	439
Business Overview [Abstract]
Number of Operating Segments | segment							2
Mortgage Insurance [Abstract]
Stock Repurchase Program, Authorized Amount									$ 202,000
Loss on Repurchase of Debt Instrument				$ 11		$ 0	$ 91,887	$ 0
Mortgage Insurance Segment
Mortgage Insurance [Abstract]
Private Mortgage Insurance Protects Lenders For Loans Made With Less Than This Maximum Down Payment Percentage				20.00%			20.00%
Percentage Of Primary Insurance On Domestic First-Lien Mortgages To Total Risk In Force				97.30%			97.30%
First Lien Primary Mortgage Insurance Risk In Force				$ 45,600,000			$ 45,600,000
Percentage Of Pool Insurance On Domestic First-Lien Mortgages To Total Risk In Force				2.50%			2.50%
Bank of America Settlement Agreement [Member] | Mortgage Insurance Segment
BAC Settlement Agreement [Abstract]
Loss Contingency, Settlement Agreement, Percentage of Subject Loans Not Held by Insureds or Are Non-GSE Investors				12.00%			12.00%
Sale of Radian Asset Assurance [Member] | Parent Company
Business Overview [Abstract]
Sale of Stock, Percentage of Ownership before Transaction		100.00%
Senior Notes Due 2020 [Member]
Mortgage Insurance [Abstract]
Long-term debt, Gross			$ 350,000
Convertible Senior Notes Due 2017
Basis of Presentation and Business Overview [Line Items]
Unamortized Debt Issuance Expense	[1]			$ 408			$ 408			$ 3,974
Mortgage Insurance [Abstract]
Long-term debt, Gross				$ 60,899			$ 60,899			450,000
Extinguishment of Debt, Amount			389,100
Loss on Repurchase of Debt Instrument			$ 91,900
New Accounting Pronouncement, Early Adoption, Effect [Member]
Basis of Presentation and Business Overview [Line Items]
Unamortized Debt Issuance Expense										17,627
New Accounting Pronouncement, Early Adoption, Effect [Member] | Convertible Senior Notes Due 2017
Basis of Presentation and Business Overview [Line Items]
Unamortized Debt Issuance Expense										$ 3,974
Scenario, Previously Reported [Member]
Basis of Presentation and Business Overview [Line Items]
Net cash provided by (used in) operating activities, continuing operations					80
Cash Provided by (Used in) Operating Activities, Discontinued Operations					12,168
Cash Provided by (Used in) Investing Activities, Discontinued Operations					9,514
Cash and Cash Equivalents, Period Increase (Decrease) Including Discontinued Operations					23,499
Net Cash Provided by (Used in) Discontinued Operations					$ (3,240)

[1] Included within long-term debt and is being amortized over the life of the convertible notes.