Note 15 - Selected Financial Information of Registrant - Radian Group Selected Financial Information of Registrant (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]
Total assets	$ 6,041,357	$ 6,656,765
Long-term Debt	659,119	818,584
Total liabilities	5,126,104	5,474,474
Total stockholders’ equity	915,253	1,182,291
Total liabilities and stockholders’ equity	6,041,357	6,656,765
Parent Company
Condensed Financial Statements, Captions [Line Items]
Investments in subsidiaries, at equity in net assets	1,412,158	1,591,914
Total assets	1,714,476	2,231,138
Long-term Debt	659,119	818,584
Total liabilities	799,223	1,048,847
Total stockholders’ equity	915,253	1,182,291
Total liabilities and stockholders’ equity	$ 1,714,476	$ 2,231,138