Note 19 - Statutory Information Risk To Capital Calculation (Details) $ in Millions		1 Months Ended	12 Months Ended
		Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) state	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Risk to Capital Line Items [Line Items]
Risk To Capital Ratio, Regulatory Maximum			25
Risk-to-capital			13.6	14.6
Other MI Companies [Member]
Risk to Capital Line Items [Line Items]
Statutory Accounting Practices, Statutory Net Income Amount			$ (6.1)	$ 92.9	$ 112.9
Statutory Accounting Practices, Statutory Capital and Surplus, Balance			57.1	55.0	473.7
Contingency reserve			1.5	1.1	140.7
Radian Insurance [Member]
Risk to Capital Line Items [Line Items]
RIF, net			35.8
Radian Guaranty [Member]
Risk to Capital Line Items [Line Items]
Statutory Accounting Practices, Statutory Net Income Amount			480.8	754.8	273.7
Statutory Accounting Practices, Statutory Capital and Surplus, Balance			1,349.7	1,686.5	1,325.2
Contingency reserve			1,260.6	860.9	389.4
RIF, net	[1]		35,357.8	36,396.1
Capital			2,041.0	2,041.4
Surplus Notes			0.0	325.0
Cumulative Earnings (Deficit)			(691.3)	(679.9)
Statutory Accounting Practice, Statutory Position			$ 2,610.3	$ 2,547.4
Risk-to-capital			13.5	14.3
Increase (Decrease) in Notes Payable, Related Parties		$ 325.0
Proceeds from Contributions from Parent				$ 100.0	$ 100.0
Parent Company
Risk to Capital Line Items [Line Items]
Related Party Transaction, Rate			0.00%
Radian Reinsurance [Member]
Risk to Capital Line Items [Line Items]
Statutory Accounting Practices, Statutory Net Income Amount			$ 60.3	(1.0)
Statutory Accounting Practices, Statutory Capital and Surplus, Balance			147.6	138.7
Contingency reserve			180.3	128.8
Proceeds from Contributions from Parent				50.0
Statutory Accounting Practices, Statutory Capital and Surplus Required			$ 20.0
Radian Mortgage Guaranty Inc. [Member]
Risk to Capital Line Items [Line Items]
Proceeds from Contributions from Parent				$ 20.0
State Insurance Regulations [Member]
Risk to Capital Line Items [Line Items]
Number Of States That Have A Statutory Or Regulatory Risk Based Capital Requirement | state			16
Minimum [Member] | Non RBC States [Member]
Risk to Capital Line Items [Line Items]
Capital Required for Capital Adequacy			$ 1.0
Maximum [Member] | Non RBC States [Member]
Risk to Capital Line Items [Line Items]
Capital Required for Capital Adequacy			$ 5.0

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