Note 14 - Selected Financial Information of Registrant - Radian Group Selected Financial Information of Registrant (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Total assets	$ 6,370,949	$ 5,903,200
Long-term Debt	906,105	663,571
Total liabilities	5,439,903	5,166,875
Total stockholders’ equity	931,046	736,325
Total liabilities and stockholders’ equity	6,370,949	5,903,200
Parent Company
Condensed Financial Statements, Captions [Line Items]
Investments in subsidiaries, at equity in net assets	1,188,325	1,234,229
Total assets	2,042,505	1,550,619
Long-term Debt	906,105	663,571
Total liabilities	1,111,459	814,294
Total stockholders’ equity	931,046	736,325
Total liabilities and stockholders’ equity	$ 2,042,505	$ 1,550,619