Note 13 - Statutory Information Risk To Capital Calculation (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2015		Dec. 31, 2014
Risk to Capital Line Items [Line Items]
Risk To Capital Ratio, Regulatory Maximum	25
Radian Guaranty [Member]
Risk to Capital Line Items [Line Items]
Percentage of New Insurance Written Attributable To States With Statutory Or Regulatory Risk Based Capital Requirements	56.30%		56.30%
Risk In Force	$ 31,324.0	[1]	$ 30,615.7	[1]
Statutory capital	1,349.4		1,325.2
Contingency reserve	487.6		389.4
Statutory Accounting Practice, Statutory Position	1,837.0		1,714.6
Risk-to-capital	17.1		17.9
Mortgage Insurance Segment | State Insurance Regulations [Member]
Risk to Capital Line Items [Line Items]
Number Of States That Have A Statutory Or Regulatory Risk Based Capital Requirement	16
Minimum [Member] | Non RBC States [Member]
Risk to Capital Line Items [Line Items]
Capital Required for Capital Adequacy	1
Maximum [Member] | Non RBC States [Member]
Risk to Capital Line Items [Line Items]
Capital Required for Capital Adequacy	$ 5

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