Note 13 - Selected Financial Information of Registrant - Radian Group Selected Financial Information of Registrant (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]
Total assets	$ 6,448,521	$ 6,656,765
Long-term Debt	674,857	818,584
Total liabilities	5,429,093	5,474,474
Total stockholders’ equity	1,019,428	1,182,291
Total liabilities and stockholders’ equity	6,448,521	6,656,765
Parent Company
Condensed Financial Statements, Captions [Line Items]
Investments in subsidiaries, at equity in net assets	1,554,749	1,591,914
Total assets	1,830,777	2,231,138
Long-term Debt	674,857	818,584
Total liabilities	811,349	1,048,847
Total stockholders’ equity	1,019,428	1,182,291
Total liabilities and stockholders’ equity	$ 1,830,777	$ 2,231,138