Note 16 - Statutory Information Risk To Capital Calculation (Details) $ in Millions		1 Months Ended
		Jun. 30, 2016 USD ($)	Sep. 30, 2016 USD ($) state	Dec. 31, 2015 USD ($)
Risk to Capital Line Items [Line Items]
Risk To Capital Ratio, Regulatory Maximum			25
Radian Guaranty
Risk to Capital Line Items [Line Items]
RIF, net (1)	[1]		$ 34,849.2	$ 36,396.1
Common stock and paid-in capital			2,041.5	2,041.4
Surplus Notes			0.0	325.0
Unassigned earnings (deficit)			(656.3)	(679.9)
Statutory policyholders’ surplus			1,385.2	1,686.5
Contingency reserve			1,156.9	860.9
Statutory capital			$ 2,542.1	$ 2,547.4
Risk-to-capital			13.7	14.3
Reportable Legal Entities [Member] | Radian Guaranty
Risk to Capital Line Items [Line Items]
Repayments of Notes Payable		$ 325.0
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
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

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