Note 15 - Selected Financial Information of Registrant—Radian Group Selected Financial Information of Registrant (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Total assets	$ 7,246,285	$ 7,620,887
Long-term Debt	814,901	964,788
Total liabilities	5,957,849	6,761,107
Total stockholders’ equity	1,288,436	859,780
Total liabilities and stockholders’ equity	7,246,285	7,620,887
Parent Company
Condensed Financial Statements, Captions [Line Items]
Investments in subsidiaries, at equity in net assets	1,408,149	947,724
Total assets	2,196,603	1,864,896
Long-term Debt	814,901	964,788
Total liabilities	908,167	1,005,116
Total stockholders’ equity	1,288,436	859,780
Total liabilities and stockholders’ equity	$ 2,196,603	$ 1,864,896