Note 15 - Statutory Information Risk To Capital Calculation (Details) $ in Millions		3 Months Ended
		Mar. 31, 2017 USD ($) state	Dec. 31, 2016 USD ($)
Risk to Capital Line Items [Line Items]
Number Of States That Have A Statutory Or Regulatory Risk Based Capital Requirement | state		16
Risk To Capital Ratio, Regulatory Maximum		25
Radian Reinsurance [Member]
Risk to Capital Line Items [Line Items]
Statutory policyholders’ surplus		$ 321.0	$ 147.6
Capital Contributions		175.0
Radian Guaranty
Risk to Capital Line Items [Line Items]
Statutory Accounting Practices, Dividends Paid with Approval of Regulatory Agency		175.0
RIF, net (1)	[1]	36,014.5	35,357.8
Common stock and paid-in capital		1,867.0	2,041.0
Unassigned earnings (deficit)		(699.3)	(691.3)
Statutory policyholders’ surplus		1,167.7	1,349.7
Contingency reserve		1,358.9	1,260.6
Statutory capital		$ 2,526.6	$ 2,610.3
Risk-to-capital		14.3	13.5
Statutory Accounting Practices, Statutory Net Income Amount		$ 94.2
Non RBC States [Member] | Minimum [Member]
Risk to Capital Line Items [Line Items]
Capital Required for Capital Adequacy		1.0
Non RBC States [Member] | Maximum [Member]
Risk to Capital Line Items [Line Items]
Capital Required for Capital Adequacy		$ 5.0
Reportable Subsegments [Member]
Risk to Capital Line Items [Line Items]
Risk-to-capital		13.4	13.6

[1] Excludes risk ceded through reinsurance contracts (to third parties and affiliates) and RIF on defaulted loans.