Note 16 - Statutory Information Risk To Capital Calculation (Details) $ in Millions		3 Months Ended
		Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Radian Guaranty
Risk to Capital Line Items [Line Items]
RIF, net	[1]	$ 41,283.5	$ 40,711.3
Common stock and paid-in capital		1,416.0	1,416.0
Surplus Note		100.0	100.0
Unassigned earnings (deficit)		(651.1)	(701.9)
Statutory policyholders’ surplus		864.9	814.1
Contingency reserve		2,224.5	2,109.9
Statutory capital		$ 3,089.4	$ 2,924.0
Risk-to-capital		13.4	13.9
Increase (decrease) in Statutory Capital and Surplus		$ 165.4
Statutory Net Income (Loss)		$ 165.1
Consolidated insurance subsidiaries
Risk to Capital Line Items [Line Items]
Risk-to-capital		12.4	12.8
Extraordinary Distribution | Radian Guaranty
Risk to Capital Line Items [Line Items]
Increase (decrease) in Statutory Capital and Surplus		$ (375.0)

[1] Excludes risk ceded through all reinsurance programs (including with affiliates) and RIF on defaulted loans.